Indian Journal of Chemistry

Sect. A: Inorganic, Bio-inorganic, Physical, Theoretical & Analytical

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CODEN: ICACEC; ISSN: 0376-4710 (Print), 0975-0975 (Online)

Special Issue on Chemical Reactivity Theory

 

VOLUME 53A

NUMBER 8-9

AUG-SEPT 2014

CONTENTS

 

929

 

Is it impossible to find the universal density functional? Or is it just well-hidden?

 

 

 

 

 

Paul W Ayers* & Robert G Parr

 

 

 

While it is generally accepted that no explicit analytic form for the exact functional exists, it is argued, based on what is known about the classical many-body problem, that this is not necessarily the case.

 

 

 

 

932

 

Thoughts upon the approaching thirtieth anniversary of two seminal coordinate scaling papers in density functional theory

 

 

 

 

 

 

 

Mel Levy

 

 

 

The significance of two seminal papers on coordinate scaling in density functional theory, [Levy & Perdew, Phys Rev A, 32 (1985) 2010 and Ghosh & Parr, J Chem Phys, 82 (1985) 3307], is discussed.

 

933

 

Limits of the concept of reactivity

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Andreas Savin

 

 

 

Despite the usefulness of concepts related to reactivity, finding a universal solution is hampered by the very nature of the problem; reactants behave differently under the influence of different reactants. Key elements in producing this diversity are degeneracy and the irrelevance of asymptotic behavior for understanding equilibrium points on the potential energy surface.

 

 

 

 

936

 

Hypervirial theorems and scaling relations in density functional theory

 

 

 

 

 

 

 

 

 

 

 

 

 

Swapan K Ghosh

 

 

 

Within the framework of density functional theory, a hypervirial theorem for an operator  is derived. The result involves the single particle electron density, r(r), and the chemical potential operator, m, of a many-electron system. Generalized scaling relations for the energy density functionals are also discussed.

 

 

 

940

 

High reactivity of triazolinediones as superelectrophiles in polar reactions: A DFT study

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Luis R Domingo* & Saeed R Emamian

 

 

 

 

 

 

Graphical Abstract.tif

 

949

 

Evaluation of hardness in Kohn-Sham theory with local density and generalized gradient approximations

 

 

 

 

 

 

 

 

 

 

 

 

 

José L Gázquez*, Badhin Gómez,
Fernando D
Hinojosa & Alberto Vela

 

 

 

Hardness of chemical species is calculated without using the frontier eigenvalues of LDA or GGA calculations.

 

 

 

958

 

Average local ionization potential within the framework of the electron localization function

 

 

 

 

 

 

 

 

 

 

 

 

 

Eduardo Chamorro*, Patricia Pérez,
Mario Duque-Noreña, Pierre Paul Romagnoli,
Daniel Pons & Mauricio González

 

 

 

A model intended to be a measure of the average local vertical ionization energy associated with the electron localization function valence population basins is explored. Comparison of computational results with the available experimental data for simple substituted isothiocyanates, provides new insights within the field for validating relationships between the spatial topology of electronic populations and energetic aspects of the bonding.

 

 

 

965

 

Local thermodynamical formalism for ensembles of excited states

 

 

 

 

 

 

 

 

 

 

 

 

 

Á Nagy

 

 

 

The thermodynamical formalism of density functional theory is generalized for ensembles of excited states. A family of novel descriptors of Coulomb systems is introduced.

 

 

 

970

 

On the relationship among Ghosh-Berkowitz-Parr entropy, Shannon entropy and Fisher information

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Chunying Rong, Tian Lu, Pratim K Chattaraj* & Shubin Liu*

 

 

 

The intrinsic relationship of the Ghosh-Berkowitz-Parr entropy with Shannon entropy and Fisher information has been revealed for both atoms and molecules. Though these quantities are found to be clearly correlated, their correlation might be complicated since no universal relationship has been observed among them.

 

 

 

978

 

Structural similarity between boron oxide Bn(BO)n2– and boron hydride BnHn2– dianions (n = 4–12)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Truong Ba Tai, Nguyen Minh Tam &
Minh Tho Nguyen
*

 

 

 

There are intriguing structural similarities between boron oxides Bn(BO)n2– and boron hydride BnHn2– dianions. The global minima of the small species, Bn(BO)n2– (n = 4–6) are analogous to those of boron hydride dianions, BnHn2–. The enhanced stabilities for the dianionic clusters, Bn(BO)n2– at n = 6, 10 and 12, follow a trend similar to that of the boron hydride dianions, BnHn2–.

 

 

 

985

 

Quantifying dispersion interaction: A study of alkane and alkene dimers

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

J Richard Premkumar, Deivasigamani Umadevi &
G Narahari Sastry
*

 

 

 

Both acyclic and cyclic hydrocarbon dimers are mainly stabilized by dispersion interaction. The dispersion energy is higher for alkane dimers for acyclic systems, while in cyclic systems a reversal of this trend is observed.

 

 

 

 

992

 

On the nature of CH62+

 

 

 

 

 

 

 

 

 

Said Jalife, Rafael Grande-Aztatzi, Diego Moreno, María A Fernández-Herrera, Edison Osorio,
Sudip Pan, Paul von Ragué Schleyer,
Gerardo Martínez-Guajardo* & Gabriel Merino
*

 

 

 

 

 

996

 

Enhanced interaction of molecular oxygen with amino acid complexes of silver and gold clusters

 

 

 

 

 

 

 

 

 

 

 

 

 

Dar Manzoor & Sourav Pal*

 

 

 

Adsorption of amino acids, glycine and alanine, enhances the reactivity of Ag4 and Au4 clusters towards O2 molecule, which is manifested by an increase in the O2 binding energy and a decrease in the M–O (M = Ag, Au) bond length. The extent of interaction is more in the case of the Au4 cluster. Also, the co-adsorption of amino acids and O2 molecule on the Ag4 and Au4 clusters is cooperative.

 

Graphicalabstract.jpg

 

 

1001

 

Unraveling the reaction mechanism, enantio and diastereoselectivities of selenium ylide promoted epoxidation

 

 

 

 

 

 

 

 

 

 

 

 

Madhavan Jaccob, Gopal Sabapathi,
J Vijaya Sundar,
P Kolandaivel*, V Subramanian*
& Ponnambalam Venuvanalingam
*

 

 

 

DFT calculations shows that initial addition transition state is the key step for deciding the enantioselectivity of the chiral selenium ylide mediated epoxidation, which is mainly governed by the steric interactions.

 

graphical abstract

 

 

1010

 

Quantum information description of reactive systems

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Roman F Nalewajski

 

 

 

 

Directions of the equilibrium current of the
(left) Hirshfeld (H) hydrogen atom in H2

 

1019

 

Electrostatics and tailoring for aggregation of small linear molecules: An ab initio study

 

 

 

 

 

 

 

 

Gurmeet Singh & Shridhar R Gadre*

 

 

 

MESP features of CO2, CS2 and OCS are utilized for a comparative study of their aggregations into small clusters.

 

 

abstract_CMYK_text.jpg

 

1031

 

Electronic stress tensor of chemical bond

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Akitomo Tachibana

 

 

 

The theory of electronic stress tensor of chemical bond on the variation principle of gravity using the semiclassical action integral has been extended to the theory using a quantum action integral based on a simple SUGRA model of gravity. The central symmetrical properties of the theory are found to be intact.

 

 

 

1036

 

A gradient-based trust radius update suitable for saddle point and transition state optimization

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Paul W Ayers* & Sandra Rabi

 

 

 

A new trust radius method, appropriate for saddle point optimization is proposed. The method ensures that the gradients from the quadratic model and the exact computed gradients are similar in direction and magnitude. For transition state optimization, the new trust radius method is found to be somewhat better than more traditional methods, based on the value of the objective function.

 

Cosine between two vectors

 
Text Box: Probability

 

 

1043

 

Soft nuclear density and nuclear repulsion

 

 

 

 

 

 

 

 

 

 

Ramon Carbó-Dorca

 

 

 

Substitution of the point-like charges by soft nuclear charges in the nuclear contribution to the total molecular energy under the Born-Oppenheimer approximation is discussed. The soft nuclear charge distribution is represented by Minkowski normalized Gaussian functions, centered at each nucleus. The general formalism is well suited to be included in ab initio calculations in a Gaussian basis LCAO MO framework, indicating that the molecular total energy surfaces must have preserved the general features, but with the new features in the absence of singularities.

 

 

1052

 

 

Polarization, reactivity and quantum molecular capacitance: From electrostatics to density functional theory

 

 

 

 

 

 

 

 

 

Patrice Delarue & Patrick Senet*

 

 

 

The electron density induced by a potential has delocalized contribution proportional to the Fukui function f(r).

 

 

 

 

 

1058

 

Solvation of graphene sheets vs. dimerization:
A theoretical study

 

 

 

 

 

 

 

Balázs Hajgató, Songül Güryel, Yves Dauphin,
Jean-Marie Blairon, Gregory Van Lier,
Hans E Miltner, Frank De Proft & Paul Geerlings
*

 

 

 

 

 

 

1064

 

Announcement

 

 

 

Authors for correspondence are indicated by (*)

 

 

 

 

 

 

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 929-931

 

 

Is it impossible to find the universal density functional? Or is it just

well-hidden?

Paul W Ayersa, * & Robert G Parrb

aDepartment of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada L8S 4M1

Email:ayers@mcmaster.ca

bDepartment of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA

Email:rgparr@email.unc.edu

Received 21 April 2014; revised and accepted 11 May 2014

We review information on methods for constructing the exact density functional mathematically and computationally. While it is generally accepted that no explicit analytic form for the exact functional exists, we argue, based on what is known about the classical many-body problem, that this is not necessarily the case.

Keywords: Theoretical chemistry, Density functional calculations, Universal density functional, Electron density

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 932

 

 

Thoughts upon the approaching thirtieth anniversary of two seminal
coordinate scaling papers in density functional theory

Mel Levy

Department of Chemistry, Duke University, Durham, North Carolina 27708, USA

Department of Physics, North Carolina A and T State University, Greensboro, North Carolina 27411, USA

Department of Chemistry and Quantum Theory Group, Tulane University, New Orleans, Louisiana 70118

Email: mlevy@tulane.edu; mplevy@ncat.edu

Received 3 July 2014; accepted 4 July 2014

The significance of two seminal papers on coordinate scaling in density functional theory, [Levy M & Perdew J P, Phys Rev A, 32 (1985) 2010 and Ghosh S K & Parr R G, J Chem Phys, 82 (1985) 3307] is discussed.

Keywords: Theoretical chemistry, Density functional calculations, Coordinate scaling, Scaling

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 933-935

 

 

Limits of the concept of reactivity

Andreas Savin

CNRS, UMR7616, Laboratoire de Chimie Théorique, F-75005 Paris, France

Sorbonne Universités, UPMC Univ Paris 06, UMR7616, Laboratoire de Chimie Théorique, F-75005 Paris, France

Email: andreas.savin@lct.jussieu.fr

Received 17 April 2014; accepted 22 April 2014

In spite of the usefulness of concepts related to reactivity, finding of a universally applicable recipe is hampered by the very nature of the problem, reactants behave differently under the influence of different reactants. Key elements in producing this diversity are degeneracy, and the irrelevance of asymptotic behavior for understanding equilibrium points on the potential energy surface. Simple examples are given to illustrate it.

Keywords: Theoretical chemistry, Chemical reactivity, Degeneracy, Quantum entanglement

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 936-939

 

 

Hypervirial theorems and scaling relations in density functional theory

Swapan K Ghosh

Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400 085, India

Email: skghosh@barc.gov.in

Received 29 May 2014: accepted 29 May 2014

Within the framework of density functional theory, a hypervirial theorem for an operator  is shown to be given by ∫dr r(r)1/2 [m,] r(r)1/2 = 0, where r(r) is the single particle electron density of a many-electron system. The chemical potential operator m expressed as either a multiplicative or a differential operator, depending on the variant of DFT, is shown to yield equivalent results. The consequence of using approximate forms of the energy density functionals are discussed and for special cases of the operator , the virial theorem in DFT is recovered. Generalised scaling relations for the energy density functionals are obtained and the implications towards tensor virial theorem are discussed.

Keywords: Theoretical chemistry, Density functional calculations, Hypervirial theorem

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 940-948

 

 

High reactivity of triazolinediones as superelectrophiles in
polar reactions: A DFT study

Luis R Domingoa, * & Saeed R Emamianb

aDepartamento de Química Orgánica, Universidad de Valencia, Dr Moliner 50, E-46100 Burjassot, Valencia, Spain
Email: domingo@utopia.uv.es

bChemistry Department, Shahrood Branch, Islamic Azad University, Shahrood, Iran

Received 28 March 2014; revised and accepted 14 April 2014

The mechanism of the polar reaction between the superelectrophile PTAD (2) and diene (6b) in the presence of THF has theoretically been studied at the MPWB1K/6-311G** level. Our investigations reveal that this reaction takes place through a stepwise mechanism via formation of intermediate (7b) with a strong zwitterionic character. The first step of the reaction, which is associated with the nucleophilic attack of diene (6b) on PTAD (2), presents complete endo selectivity. Formation of the expected formal [4+2] cycloadduct (8b) quickly takes place through a ring closure process which is much favoured both energetically and geometrically. However, formation of (8b) is a reversible process. Interestingly, intermediate (7b) undergoes a 1,7-hydrogen shift process yielding the major ene adduct (9b), which is thermodynamically very stable. Analysis of relative Gibb free energies suggests that while the expected formal [4+2] cycloadduct (8b) is obtained under kinetic control, the experimentally observed ene adduct (9b) is formed under thermodynamic control. Finally, analysis of the DFT reactivity indices of the reagents accounts for the high reactivity of PTAD (2) acting as a superelectrophile, and the asynchronicity found in the C-N single bond formation as a consequence of the asymmetric nucleophilic activation of diene system of (6b).

Keywords: Theoretical chemistry, Chemical reactivity, Superelectrophiles, Density functional calculations, Triazolinediones

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 949-957

 

 

Evaluation of hardness in Kohn-Sham theory with local density and
generalized gradient approximations

José L Gázqueza, *, Badhin Gómeza, Fernando D Hinojosab & Alberto Velab

aDepartamento de Química, Universidad Autónoma Metropolitana-Iztapalapa,
Av.
San Rafael Atlixco 186, México, D. F. 09340, México

Email: jlgm@xanum.uam.mx

bDepartamento de Química, Centro de Investigación y de Estudios Avanzados,
Av.
Instituto Politécnico Nacional 2508, México, D. F. 07360, México

Received 29 April 2014; revised and accepted 3 June 2014

By making use of Janak’s interpolation in the Kohn-Sham method, together with an explicit and differentiable functional of the density for the exchange-correlation energy, like LDA or GGA, the second derivative of the energy with respect to the number of electrons, N, is evaluated from the derivative of the highest occupied molecular orbital (HOMO) with respect to N (left derivative), or from the derivative of the lowest unoccupied molecular orbital (LUMO) with respect to N (right derivative). Both cases lead to expressions that may be evaluated from a single post-SCF calculation that avoids the use of the frontier orbitals eigenvalues. The results obtained for two test sets of molecules and for several atoms indicate that both provide a better description than the LUMO-HOMO eigenvalue difference and that the left derivative seems to lead to more confident results than the right derivative.

Keywords: Theoretical chemistry, Density functional calculations, Kohn-Sham theory, Chemical reactivity, Chemical potential, Hardness, Softness

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 958-964

 

 

Average local ionization potential within the framework of the
electron localization function

Eduardo Chamorroa, *, Patricia Péreza, Mario Duque-Noreñaa, Pierre Paul Romagnolib,
Daniel Ponsb & Mauricio Gonzálezc

aDepartamento de Ciencias Quimicas, bDepartmento de Matematicas, c Departamento de Física, Facultad de Ciencias Exactas, Universidad Andres Bello. Avenida República 275, 8370146, Santiago, Chile

Email: echamorro@unab.cl

Received 25April 2014; revised and accepted 9 May 2014

In this work we explore new insights arising from simple indices intended to measure the average local vertical ionization energy associated to ELF valence population basins. The model has been computationally tested on simple isothiocyanate compounds (R-N=C=S) revealing that the proposed relationships correctly establish both the inductive and electronegativity effects of electronegative groups along the examined series, i.e., methyl- < germyl- < hydrogen- < acetyl- < chlorodifluoroacetyl-, in agreement with the available experimental observations. The proposed energetical descriptors are expected to contribute to the search of relationships between the spatial topology of electronic populations and energetical aspects of the bonding. The present results enhance the possibility of gaining insight into chemical bonding and reactivity within the ELF topological-defined framework of chemical rationalization.

Keywords: Theoretical chemistry, Ionization potential, Electron localization function, Chemical reactivity, Nucleophilicity, Isothiocyanates, Valence basin populations, Lone pairs

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 965-969

 

 

Local thermodynamical formalism for ensembles of excited states

Á Nagy

Department of Theoretical Physics, University of Debrecen, Debrecen, Hungary

Email: anagy@phys.unideb.hu

Received 28 March 2014; revised and accepted 7 April 2014

The thermodynamical formalism of density functional theory is generalized for ensembles of excited states. Ensemble local temperature is defined. A family of novel descriptors of Coulomb systems is introduced.

Keywords: Theoretical chemistry, Density functional calculations, Excited states

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 970-977

 

 

On the relationship among Ghosh-Berkowitz-Parr entropy,
Shannon entropy and Fisher information

Chunying Ronga, Tian Lub, Pratim K Chattarajc, * & Shubin Liua, d, *

aKey Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China)
and Key Laboratory of Resource Fine-Processing and Advanced Materials of Hunan Province, College of Chemistry
and Chemical Engineering, Hunan Normal University, Changsha Hunan 410081, PR China

bSchool of Chemical and Biological Engineering, University of Science and Technology Beijing, Beijing, PR China

cDepartment of Chemistry and Center for Theoretical Studies, Indian Institute of Technology, Kharagpur 721 302, India

Email: pkc@chem.iitkgp.ernet.in

dResearch Computing Center, University of North Carolina, Chapel Hill, North Carolina 27599-3420, USA

Email: shubin@email.unc.edu

Received 11 April 2014; revised and accepted 15 May 2014

In their seminal work thirty years ago, Ghosh, Berkowitz, and Parr reformulated the ground-state density-functional theory into a local version of thermodynamics, where a new concept, called Ghosh-Berkowitz-Parr entropy, was proposed. Employing the non-interacting kinetic energy density and Thomas-Fermi kinetic energy density, this entropy was formulated like the Sackur-Tetrode equation in classical thermodynamics. Not much has been known about its properties. In this contribution, we investigate its relationship with Shannon entropy and Fisher information from the numerical perspective. To that end, we have examined 36 neutral atoms and 42 molecular systems. We have considered both molecular and atomic contributions with Bader’s zero-flux criterion to partition atoms in molecules. Our results show that these quantities are closely correlated, and yet their correlations might be complicated since no universal relationship among them has been observed.

Keywords: Theoretical chemistry, Density functional calculations, Entropy, Ghosh-Berkowitz-Pan entropy, Shannon entropy, Fisher information, Electron density

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 978-984

 

 

Structural similarity between boron oxide Bn(BO)n2– and
boron hydride BnHn2– dianions (n = 4–12)

Truong Ba Tai a, Nguyen Minh Tam a, b & Minh Tho Nguyena, b, *

aDepartment of Chemistry, KU Leuven, B-3001 Leuven, Belgium

bInstitute for Computational Science and Technology at Ho Chi Minh City (ICST), Vietnam

Email: minh.nguyen@chem.kuleuven.be

Received 8 April 2014; revised and accepted 13 April 2014

The boron oxide dianions Bn(BO)n2– (n = 4–12) are studied using DFT (B3LYP) method. Geometries of the global minima of Bn(BO)n2– with n = 4–12 are found to be analogous to those of boron hydrides. All boron oxides considered exhibit large HOMO-LUMO gaps and high vertical detachment energies. Similar to BnHn2–, the enhanced thermodynamic stabilities are established for Bn(BO)n2– at n = 6, 10 and 12. Due to the strength of BO bonds, oxidation of boron clusters thus consistently leads to formation of exohedral boronyls that in turns behave as substituents replacing the hydrogen atoms. This structural similarity allows the shape of boron oxides to be predicted from boron hydrides. Nevertheless, the BO bonds are expected to be the preferred reaction sites of boron oxides.

Keywords: Theoretical chemistry, Boron oxides, Boron hydrides, Exohedral boronyls, Structural similarity

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 985-991

 

 

Quantifying dispersion interaction: A study of alkane and alkene dimers

J Richard Premkumar, Deivasigamani Umadevi & G Narahari Sastry*

CSIR-Centre for Molecular Modelling, Indian Institute of Chemical Technology, Hyderabad 500 607, India

Email: gnsastry@gmail.com

Received 20 April 2014; revised and accepted 2 May 2014

In this study, the interaction pattern and energies of a series of hydrocarbon dimers have been investigated by using a highly reliable quantum chemical method (M06-2X/cc-pVTZ). Saturated and unsaturated hydrocarbons in both cyclic and acyclic forms have been modelled to study their interaction. These dimers are found to involve different types of noncovalent interactions such as p-p  (dimer of unsaturated hydrocarbons), CH×××p (dimer of saturated-unsaturated hydrocarbons) and CH×××HC (dimer of saturated hydrocarbons). Atoms in molecules analysis provides further insight into the presence of these different noncovalent interactions. Interestingly, the saturated hydrocarbon dimers (A-A) are found to have binding energy strengths comparable with those of the dimers of their unsaturated counterparts (E-E). Strong interactions have been observed between the saturated monomers with the corresponding unsaturated monomers (A-E). The energy decomposition analysis using DFT-SAPT method reveals that both dispersion and electrostatic components play nearly equal roles in modulation of the strength of the hydrocarbon-hydrocarbon interaction.

Keywords: Theoretical chemistry, Density functional calculations, Dispersion, Noncovalent interactions, Hydrocarbon interactions, Alkane dimers, Alkene dimers, Dimers, Hydrocarbon dimers,
Energy decomposition analysis

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 992-995

 

 

On the nature of CH62+

Said Jalifea, Rafael Grande-Aztatzia, Diego Morenoa, María A Fernández-Herrerab, Edison Osorioc, Sudip Pand,
Paul von Ragué Schleyer e, Gerardo Martínez-Guajardoa, f, * & Gabriel Merinoa, *

aDepartamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados,
Unidad Mérida. Km 6 Antigua Carretera a Progreso Apdo. Postal 73, Cordemex, 97310, Mérida, Yucatán, México
Email: gmerino@mda.cinvestav.mx

bFacultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla. Ciudad Universitaria, 72570, Puebla, México

cDepartamento de Ciencias Básicas, Fundación Universitaria Luis Amigó, SISCO, Transversal 51A # 67B 90,
Medellín, Colombia

dDepartment of Chemistry and Centre for Theoretical Studies, Indian Institute of Technology Kharagpur,
Kharagpur 721 302, India

eCenter for Computational Chemistry, University of Georgia, Athens, Georgia 30602, USA

fUnidad Académica de Ciencias Químicas, Área de Ciencias de la Salud, Universidad Autónoma de Zacatecas, Km. 6 carretera Zacatecas-Guadalajara s/n, Ejido La Escondida C P 98160, Zacatecas, México

Email: germtz86@gmail.com

Received 26 April 2014, revised and accepted 18 May 2014

The meta-stability of the hexacoordinate CH62+ dication in the gas phase is confirmed by a detailed computational exploration of its potential energy surface, using a modified “Kick” heuristic methodology and by Born-Oppenheimer Molecular-Dynamics simulations to assess its kinetic persistence. The transition states for deprotonation, decomposition into CH3+ and H3+, hydrogen scrambling, and H-H rotation are found. In addition, a nearly perfect correlation between the protonation affinities and their coordination number is obtained.

Keywords: Theoretical chemistry, Kick heuristic methodology, Born-Oppenheimer molecular dynamics study,
Kinetic stability
, Adaptive natural density partitioning analysis

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 996-1000

 

 

Enhanced interaction of molecular oxygen with amino acid complexes
of silver and gold clusters

Dar Manzoor & Sourav Pal*

Theoretical Chemistry Group, CSIR-National Chemical Laboratory, Pune 411 008, India

Email: s.pal.ncl.res.in

Received 19 April 2014 ; accepted 13 May 2014

Density functional theory calculations have been carried out to study the effect of amino acid adsorption on the reactivity of silver and gold clusters with molecular oxygen. It is found that the amino acids glycine and alanine form stable complexes with both Ag4 and Au4 clusters. However, the extent of interaction is more in the case of the Au4 cluster, as reflected from the increase in binding energy in the amino acid Au4 complexes. Our results confirm that the adsorption of amino acids glycine and alanine enhances the reactivity of Ag4 and Au4 clusters towards O2 molecule. The enhanced reactivity of O2 molecule towards the amino acid metal cluster complexes is manifested by an increase in the O2 binding energy and a decrease in the M–O (M = Ag, Au) bond length. Moreover, it is found that the co-adsorption of amino acids and O2 molecule on the Ag4 and Au4 clusters is cooperative.

Keywords:   Theoretical chemistry, Density functional calculations, Metal clusters, Gold clusters, Silver clusters,
Amino acid complexes

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 1001-1009

 

 

Unraveling the reaction mechanism, enantio and diastereoselectivities of
selenium ylide promoted epoxidation

Madhavan Jaccoba, †, Gopal Sabapathia, J Vijaya Sundarb, P Kolandaivelc, *, V Subramanianb, * &
Ponnambalam Venuvanalingama, *

aTheoretical and Computational Chemistry Laboratory, School of Chemistry, Bharathidasan University,
Tiruchirappalli 620 024, Tamil Nadu, India

Email: venuvanalingam@yahoo.com

bChemical Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600 020, Tamil Nadu, India

Email: subuchem@hotmail.com

cDepartment of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu, India

Email: ponkvel@hotmail.com

Received 22 April 2014; revised and accepted 10 May 2014

The reaction between chiral selenium ylide and benzaldehyde leads to the formation of (2S,3S)-trans-epoxide with high enantio- and diastereoselectivity. Density functional theory and Hartree-Fock calculations using 6-31G(d) basis set have been performed to understand the reaction mechanism and factors associated with enantio- and diastereoselectivities. Conformation of chiral selenium ylide has been found to have a strong influence on the stability of the initial addition transition state between ylide and benzaldehyde. Calculated enantio- and diastereoselectivities from the energy differences between B3LYP/6-31G(d) addition TSs are in good agreement with the experimental data. The rate and diastereoselectivity are controlled by the cisoid-transoid rotational transition state. Analysis of transition state geometries clearly reveals that unfavorable eclipsing interaction between phenyl groups of the benzaldehyde and ylidic substituents mainly governs the energy differences between the enantio and diastereomeric transition states. The favourable reactivity is also explained through Fukui function calculations.

Keywords: Theoretical chemistry, Density functional calculations, Selenium ylides, Epoxidation, Enantio, Stereoselectivity, Diastereoselectivity, Fukui functions

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 1010-1018

 

 

Quantum information description of reactive systems

Roman F Nalewajski

Department of Theoretical Chemistry, Jagiellonian University, R. Ingardena 3, 30-060 Cracow, Poland

Email: nalewajs@chemia.uj.edu.pl

Received 14 February 2014; accepted 12 March 2014

Information Theory (IT) of molecular electronic states is applied to describe equilibria in separate reactants and reactive system as a whole. It uses the resultant (quantum) measures of the information content in electronic states, determined by both the classical (probability/density) functionals and their non-classical (phase/current)-related complements. The intra-reactant (fragment) equilibrium state in the separate reactant is uniquely characterized by its equilibrium phase related to its own electron distribution, while the inter-reactant (molecular) equilibrium state reflects the stationary electron density of the whole reactive system. The probability currents of the non-bonded reactants, e.g., the isolated fragments or their mutually-closed analogs in the system “promolecular” reference, and of the bonded (mutually-open) fragments in the whole reactive system, are compared to identify the current-promotion of these subsystems. The illustrative case of the two-orbital (2-electron) system is examined in some detail to generate the combination formula for the overall current and to identify its additive and non-additive components. Electron communications between reactants are examined and IT descriptors of the multiplicity and covalent/ionic composition of chemical bonds are related to the additive and non-additive information contributions in local and atomic orbital resolutions.

Keywords: Communication systems, Current promotion of reactants, Electronic communications in molecules, Information theory, Molecular information channels, Probability currents, Quantum information measures, Reactive systems

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 1019-1030

 

 

Electrostatics and tailoring for aggregation of small linear molecules:
An ab initio study

Gurmeet Singh & Shridhar R Gadre*

Department of Chemistry, Indian Institute of Technology, Kanpur 208 016, India

Email: gadre@iitk.ac.in

Received 8 April 2014; accepted 3 May 2014

Features of the molecular electrostatic potential (MESP) for three linear triatomic molecules, viz., CO2, CS2 and OCS are utilized for a comparative study of their aggregation into small clusters. Trial structures of clusters upto tetramers, generated by using the MESP insights, are subjected to geometry optimization employing second-order Møller-Plesset (MP2) theory, with correlation consistent aug-cc-pvTZ (aTZ) basis set. Single point energies at MP2/aQZ levels are calculated for the estimation of binding energies at complete basis set (CBS) limit. Calculations at the coupled cluster singles and doubles with perturbative triples (CCSD(T)) level are also reported for the most favorable tetramers using the molecular tailoring approach (MTA). Geometrical parameters such as rotational constants thus obtained are found to be in good agreement with the corresponding experimental ones. Minimal nature of the reported structures is confirmed by the vibrational frequency calculations at MP2/aDZ level of theory. The current work offers some hints towards the patterns in the oligomer formation for these molecules and a comparison of the motifs found in the corresponding crystal structure is made.

Keywords: Theoretical chemistry, Ab initio calculations, Molecular clusters, Second-order Møller-Plesset theory, Coupled cluster singles and doubles with perturbative triples, Molecular electrostatic potential,
Molecular tailoring approach

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 1031-1035

 

 

Electronic stress tensor of chemical bond

Akitomo Tachibana*

Department of Micro Engineering, Kyoto University, Kyoto 615-8540, Japan

Email: akitomo@scl.kyoto-u.ac.jp

Received 28 March 2014; accepted 11 April 2014

Electronic stress tensor of chemical bond  is a 3-dim real symmetric component of a 3-dim real stress tensor . The complementary antisymmetric component  drives the torque of electron spin  through the vorticity . The whole picture has quite recently been unified on the variation principle of gravity using the semiclassical action integral. This theory is extended in this paper using a quantum action integral based on a simple SUGRA (supergravity), which is a simple SUSY (supersymmetry) model of gravity.

Keywords: Stress tensor, Electronic stress tensor, Energy density, Semiclassical action integral,
Quantum action integral

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 1036-1042

 

 

A gradient-based trust radius update suitable for saddle point and
transition state optimization

Paul W Ayers* & Sandra Rabi

Department of Chemistry & Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada

Email: ayers@chemistry.mcmaster.ca

Received 23 April 2014; accepted 25 April 2014

A new trust radius method, appropriate for saddle point optimization is proposed. The idea is to ensure that the gradients from the quadratic model, and the exact computed gradients, are similar in direction and magnitude. For transition state optimization, the new trust radius method is found to work somewhat better than more traditional methods, based on the value of the objective function.

Keywords: Theoretical chemistry, Saddle point optimization, Transition state optimization, Trust radius method

 

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 1043-1051

 

 

Soft nuclear density and nuclear repulsion

Ramon Carbó-Dorca

Institut de Química Computacional i Catàlisi, Universitat de Girona, Catalonia, Spain

Email: quantumqsar@hotmail.com

Received 2 April 2014; accepted 9 May 2014

This paper proposes the description of a soft nuclear density and the associated soft nuclear Coulombic repulsion. The idea just consists into describing soft nuclear repulsion expressions substituting the usual point-like nuclear charge density by means of a Gaussian distribution. The theoretical structure and management of such an approach is discussed.

Keywords: Theoretical chemistry, Born-Oppenheimer approximation, Nuclear density, Soft nuclear density, Nuclear repulsion, Soft nuclear repulsion

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 1052-1057

 

 

Polarization, reactivity and quantum molecular capacitance: From electrostatics to density functional theory

Patrice Delarue & Patrick Senet*

Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université de Bourgogne, Dijon, France

Email: psenet@u-bourgogne.fr

Received 31 March 2014; revised and accepted 6 May 2014

The charge distribution induced by an inhomogeneous electric potential applied to a molecule is in fact the sum of two terms: polarization (localized) and chemical (delocalized) charge distributions. The chemical induced charge distribution is proportional to the inhomogeneous response of the molecule to an electron transfer (Fukui function). Analogy with the electrostatic Thomson theorem for the perfect conductors permits to define the quantum molecular capacitance.

Keywords: Theoretical chemistry, Density functional calculations, Polarization, Chemical reactivity, Electrostatics, Quantum molecular capacitance, Fukui function

 

Indian Journal of Chemistry

Vol. 53A, Aug-Sept 2014, pp. 1058-1063

 

 

Solvation of graphene sheets vs. dimerization: A theoretical study

Balázs Hajgatóa, Songül Güryela, Yves Dauphinb, Jean-Marie Blaironb, Gregory Van Liera,
Hans E Miltnerb, Frank De Profta & Paul Geerlingsa, *

aFree University of Brussels - Vrije Universiteit Brussel (VUB), Research Group General Chemistry (ALGC),
Pleinlaan 2, B-1050 Brussels, Belgium

Email: pgeerlin@vub.ac.be

bSOLVAY S.A., Innovation Center, Ransbeekstraat 310, B-1120 Brussels, Belgium

Received 6 May 2014; accepted 16 May 2014

Thermodynamic stability of graphene against stacking in the gas phase and in different solvents (N-methyl-2-pyrrolidone), dimethyl sulfoxide, and water) has been investigated using the semi-empirical PM6 method combined with supermolecular approach, and with Periodic Boundary Conditions using Density Functional Theory in conjunction with the Perdew-Burke-Erzernhof functional. In the case of a supermolecular approach, the effect of the ratio of the edge and the center part on the solvation enthalpy has also been investigated.

Keywords: Thermodynamic stability, Graphene, Dimerization, Stacking, Solubility