01966nas a2200241 4500008004100000020001800041022001400059245007800073210006900151260009500220300001200315490000600327520112400333653003001457653002501487653001901512653002201531100001601553700001801569700001601587700001301603856010801616 2005 eng d a90-6764-442-0 a1573-419600aDensity functional response approach for electric properties of molecules0 aDensity functional response approach for electric properties of  aCorinth, GreecebVsp BV-C/o Brill Acad Publ, Po Box 9000, 2300 Pa Leiden, NetherlandscOCT a142-1510 v33 a

We review in this paper an implementation of the response approach to the Kohn-Sham (KS) density functional theory (DFT) for obtaining the linear and non-linear electric response properties of molecules using Gaussian type orbital basis centered on atoms. We have made a formulation in which the response of the electron density through the solution of the coupled perturbed Kohn-Sham (CPKS) equations has to be obtained only once, instead of iteratively as in the case of completely analytic procedure. Our method is based on a numerical finite-field solution of derivative KS operator, followed by analytic solution of CPKS equation. Further, using the response of the electron density, the dipole moment, polarizability and first-hyperpolarizability of the molecules are evaluated. The method is particularly useful for large systems. We tested our method using HF, BH, H2O and CO as test molecules, for which, high quality ab initio results are available. Further, our study of possible incorporation of non-dynamical electron correlation by studying BH and HF at several internuclear distances is discussed.

10aDensity functional theory10amolecular properties10apolarizability10aResponse approach1 aPal, Sourav1 aSophy, K., B.1 aMaroulis, G1 aSimos, T uhttps://library.ncl.res.in/content/density-functional-response-approach-electric-properties-molecules-000892nas a2200169 4500008004100000022001400041245020100055210006900256260007100325300001200396490000600408520011900414100001800533700002500551700001600576856013000592 2007 eng d a1549-961800aDensity functional static dipole polarizability and first-hyperpolarizability calculations of Na-n (n=2, 4, 6, 8) clusters using an approximate CPKS method and its comparison with MP2 calculations0 aDensity functional static dipole polarizability and firsthyperpo a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAY a716-7270 v33 a

{We report the static dipole polarizability and first-hyperpolarizability of the sodium atom clusters, Na-n

1 aSophy, K., B.1 aCalaminici, Patrizia1 aPal, Sourav uhttps://library.ncl.res.in/content/density-functional-static-dipole-polarizability-and-first-hyperpolarizability-calculations01693nas a2200193 4500008004100000022001400041245009600055210006900151260007100220300001400291490000800305520097000313100001901283700001601302700002101318700002101339700001601360856012301376 2007 eng d a1089-563900aDeprotonation of 1,2-dialkylpyridinium ions: a DFT study of reactivity and site selectivity0 aDeprotonation of 12dialkylpyridinium ions a DFT study of reactiv a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP a8823-88280 v1113 a

A site-selectivity model, based on the Fukui function as a local reactivity descriptor, has been applied to 1.2-disubstituted pyridinium ions incorporating two competing sites of similar reactivity, i.e., 1-methylene and 2-methylene, which may undergo deprotonation depending on the nature of substituent present on these moieties. Applicability of the local HSAB rule, in context with the Li-Evans' generalized HSAB principle suggesting the hard-hard interactions to be controlled by minimum Fukui function, has been illustrated. Global and local reactivity descriptors have been computed by carrying out DFT calculations at B3LYP/6-31++G** level using Mulliken and NPA methods for charge analysis. A comparison with the calculated deprotonation energies involving two sites indicates that the observed site selectivity in differently substituted pyridinium ions is better explained by the Li-Evans rule of minimum Fukui function for hard-hard interactions.

1 aGupta, Neelima1 aGarg, Reena1 aShah, Kirti, Kr.1 aTanwar, Akhilesh1 aPal, Sourav uhttps://library.ncl.res.in/content/deprotonation-12-dialkylpyridinium-ions-dft-study-reactivity-and-site-selectivity-001343nas a2200157 4500008004100000022001400041245015500055210006900210260007300279300001200352490000800364520064400372100002801016700001601044856012501060 2007 eng d a0009-261400aDipole moments and polarizabilities of some small radicals using constrained variational response to fock-space multi-reference coupled-cluster theory0 aDipole moments and polarizabilities of some small radicals using aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAPR a321-3250 v4383 a

In this Letter, we present dipole moments and polarizabilities of some open-shell doublet radicals, obtained analytically using constrained variational response to Fock-space (FS) multi-reference (MR) coupled cluster (CC) theory. These radicals can be treated as electron attached (EA) states of the corresponding closed-shell cations. Additionally, we also report analytical polarizabilities of some doublet radicals, which can be considered as ionized (IP) states of the corresponding anions. We compare our results with finite field FSMRCC response and the available benchmark results. (c) 2007 Elsevier B.V. All rights reserved.

1 aManohar, Prashant, Uday1 aPal, Sourav uhttps://library.ncl.res.in/content/dipole-moments-and-polarizabilities-some-small-radicals-using-constrained-variational02127nas a2200229 4500008004100000022001400041245013700055210006900192260007700261300001200338490000600350520124500356653001901601653003601620653001301656653002101669653001901690100001901709700001601728700002301744856013001767 2008 eng d a1439-423500aDensity functional investigations of electronics structure and dehydrogenation reactions of Al- and Si-substituted magnesium hydride0 aDensity functional investigations of electronics structure and d aPO BOX 10 11 61, D-69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcAPR a928-9340 v93 a

{The effect on the hydrogen storage attributes of magnesium hydride (MgH2) of the substitution of Mg by varying fractions of Al and Si is investigated by an ab initio plane-wave pseuodopotential method based on density functional theory. Three supercells, namely, 2 x 2 x x 3 x 1 x 1 and 5 x 1 x 1 are used for generating configurations with varying amounts (fractions x=0.0625, 0.1, and 0.167) of impurities. The analyses of band structure and density of states (DOS) show that, when a Mg atom is replaced by Al, the band gap vanishes as the extra electron occupies the conduction band minimum. In the case of Si-substitution, additional states are generated within the band gap of pure MgH2-significontly reducing the gap in the process. The reduced band gaps cause the Mg-H bond to become more susceptible to dissociation. For all the fractions, the calculated reaction energies for the stepwise removal of H-2 molecules from Al- and Si-substituted MgH2 ore much lower than for H-2 removal from pure MgH2. The reduced stability is also reflected in the comparatively smaller heats of formation (Delta H-f) of the substituted MgH2 systems. Si causes greater destabilization of MgH2 than Al for each x. For fractions x = 0.167 of Al

10aband structure10aDensity functional calculations10ahydrides10aHydrogen storage10aThermodynamics1 aKelkar, Tuhina1 aPal, Sourav1 aKanhere, Dilip, G. uhttps://library.ncl.res.in/content/density-functional-investigations-electronics-structure-and-dehydrogenation-reactions-al-001892nas a2200169 4500008004100000022001400041245012200055210006900177260007100246300001400317490000800331520118500339100002401524700002601548700001601574856013201590 2009 eng d a1932-744700aDensity functional investigation of relativistic effects on the structure and reactivity of tetrahedral gold clusters0 aDensity functional investigation of relativistic effects on the  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAPR a7101-71060 v1133 a

The influence of relativistic effects on the structure, vibrational modes, and reactivity of recently discovered tertrahedral gold clusters (Au(19) and Au(20)) are investigated using density functional methods. The intramolecular reactivity of the clusters was analyzed using density functional-based reactivity descriptors. The work shows that whereas the structural properties and vibrational modes are considerably affected by the relativistic effects, the reactivity trends based on Fukui function calculation on various atoms within this cluster remain unaffected by the absence or presence of relativistic effects. The reactivity descriptors reveal that the vertex atoms are the most reactive ones in Au(20) toward a nucleophilic attack. On the other hand, atoms connecting the missing vertex edge with the pyramid base along with the vertex atom are the most reactive for a nucleophilic attack in Au(19). The atoms lying at the center of each face are favorable for an electrophilic attack in both cases. Interestingly, the atoms with a missing cap in Aulg are highly favorable for electrophilic attack, and Au(20) has more sites for a favorable nucleophilic attack.

1 aDe, Himadri, Sekhar1 aKrishnamurty, Sailaja1 aPal, Sourav uhttps://library.ncl.res.in/content/density-functional-investigation-relativistic-effects-structure-and-reactivity-tetrahedral-001342nas a2200253 4500008004100000020004100041022001400082245008500096210006900181260006700250300001200317490000800329520042300337653004100760653002600801653003400827653000900861653001500870653003300885100001600918700001700934700002200951856011500973 2012 eng d a978-3-642-32753-7; 978-3-642-32752-0 a0081-599300aDescriptors as probes for inter-molecular interactions and external perturbation0 aDescriptors as probes for intermolecular interactions and extern a233 Spring Street, New York, NY 10013, United StatesbSpringer a131-1580 v1493 a

In this article, different reactivity descriptors have been reviewed. Conceptual density functional theory is an important area where a lot of interesting developments in terms of descriptors and molecule interactions have taken place in recent years. This review will highlight our own work on such development of descriptors and their applications to characterise stability and reactivity in molecule systems.

10aConceptual density functional theory10aElectric field effect10aGlobal reactivity descriptors10aHSAB10aLocal HSAB10aLocal reactivity descriptors1 aPal, Sourav1 aPutz, M., V.1 aMingos, D., M. P. uhttps://library.ncl.res.in/content/descriptors-probes-inter-molecular-interactions-and-external-perturbation-002012nas a2200169 4500008004100000022001400041245007600055210006900131260007100200300001600271490000800287520137800295100001701673700001601690700002601706856011001732 2014 eng d a1932-744700aDinitrogen activation by silicon and phosphorus doped aluminum clusters0 aDinitrogen activation by silicon and phosphorus doped aluminum c a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAUG a19869-198780 v1183 a

N-2 reduction is crucial for life, and very few catalysts are currently available to carry out this process at ambient temperature and pressure. In the present work, density functional theory based calculations reveal doped aluminum clusters to be highly reactive toward molecular nitrogen and hence are prospective materials for its activation at low temperatures. Calculations on silicon and phosphorus doped aluminum clusters with 5-8 atoms demonstrate an enhanced N-2 activation with respect to their pristine ground state and high energy counterparts. This increased efficiency of N-2 activation by doped ground state Al clusters is corroborated by an increment of the N N bond length, a red shift in N N bond stretching frequency, and adsorption energy (E-ad). Ab initio molecular-dynamics simulations demonstrate consequential efficiency of doped clusters toward dinitrogen activation at finite temperature. The ability of doped clusters toward activation of molecular nitrogen is site and shape sensitive. In short, this theoretical study highlights the critical role of doping foreign impurities for future endeavors in the design of cost-effective and efficient catalysts for N-2 activation at ambient temperatures. This observation may spur further studies in the field of aluminum nanocatalysis by doping silicon and phosphorus atom in aluminum clusters.

1 aDas, Susanta1 aPal, Sourav1 aKrishnamurty, Sailaja uhttps://library.ncl.res.in/content/dinitrogen-activation-silicon-and-phosphorus-doped-aluminum-clusters-001246nas a2200157 4500008004100000245009900041210006900140260000800209300001600217490000800233520065900241100001800900700002600918700001600944856012800960 2017 eng d00aDissociative adsorption of molecular hydrogen on BN-doped graphene-supported aluminum clusters0 aDissociative adsorption of molecular hydrogen on BNdoped graphen cNOV a26493-264980 v1213 aThe present work demonstrates dissociative adsorption of molecular hydrogen on supported and unsupported aluminum Wclusters (Al-n, n = 4-8, 13) using density functional theory based calculations. The studies reveal that the presence of a BN-doped graphene surface support reduces the dissociative adsorption barrier of the bond in molecular hydrogen on even atom clusters. In particular, supported Al-6 demonstrates a barrier-less dissociative adsorption toward the H-2 molecule. These results demonstrate the excellent potential of supported Al nanoparticles for hydrogen storage and also the potential of doped graphene systems are catalyzing supports.1 aKumar, Deepak1 aKrishnamurty, Sailaja1 aPal, Sourav uhttps://library.ncl.res.in/content/dissociative-adsorption-molecular-hydrogen-bn-doped-graphene-supported-aluminum-clusters01431nas a2200193 4500008004100000022001500041245012700056210006900183260000800252300001600260490000700276520071800283100001801001700002501019700002601044700002701070700001601097856012401113 2018 eng d a 1463-907600aDissociative chemisorption of hydrogen molecules on defective graphene-supported aluminium clusters: a computational study0 aDissociative chemisorption of hydrogen molecules on defective gr cNOV a26506-265120 v203 a

Using periodic density functional theory-based calculations, in the present study, we address the chemical bonding between aluminium clusters (Al-n, n = 4-8 and 13) and monovacant defective graphene. The adsorption strength of the above-mentioned aluminium clusters is fivefold (approximate to 3 to 5 eV) higher on defective graphene as compared to the earlier reported values on non-defective graphene and BN-doped graphene. The Bader charge analysis and different charge densities reveal that this adsorption is driven by significant charge transfer from the Al clusters to defective graphene. Thus, chemisorbed Al clusters demonstrate high activity towards dissociative adsorption of molecular hydrogen.

1 aKumar, Deepak1 aGovindaraja, Thillai1 aKrishnamurty, Sailaja1 aKaliaperumal, Selvaraj1 aPal, Sourav uhttps://library.ncl.res.in/content/dissociative-chemisorption-hydrogen-molecules-defective-graphene-supported-aluminium