01276nas a2200169 4500008004100000022001400041245014400055210006900199260012500268300002300393490000800416520050200424100002100926700001800947700001600965856012500981 2006 eng d a0021-960600aInteraction induced shifts in O-H stretching frequency of water in halide-ion water clusters: a microscopic approach with a bond descriptor0 aInteraction induced shifts in OH stretching frequency of water i aCIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScDEC aArticle No. 2143040 v1253 a

Based on conceptual density functional theory, two new descriptors, the normalized atom-condensed Fukui functions (NFFs) and bond deformation kernel (BDK), are proposed to describe the O-H stretching frequency shifts in water halide-ion clusters by including local polarizations in the system. NFF, along with BDK, can be successfully used to describe interactions between different atoms, especially in cases where polarizations are quite important. (c) 2006 American Institute of Physics.

1 aTanwar, Akhilesh1 aBagchi, Biman1 aPal, Sourav uhttps://library.ncl.res.in/content/interaction-induced-shifts-o-h-stretching-frequency-water-halide-ion-water-clusters-101694nas a2200169 4500008004100000022001400041245013200055210006900187260007100256300001200327490000800339520098900347100001501336700002801351700001601379856012901395 2007 eng d a1089-563900aInfluence of electric field on the global and local reactivity descriptors: reactivity and stability of weakly bonded complexes0 aInfluence of electric field on the global and local reactivity d a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJAN a375-3830 v1113 a

The response of the global and local reactivity density-based descriptors (chemical potential, hardness, softness, Fukui function, and local softness) in the presence of external electric field has been studied for some of the simple prototype molecular systems. In addition to the analysis on the reactivity of these systems, the influence of the electric field on the interaction energy of the complexes formed by these systems has also been studied using the recently proposed semiquantitative model based on the local hard-soft acid-base principle. By using the inverse relationship between the global hardness and softness parameters, a simple relationship is obtained for the variation of hardness in terms of the Fukui function under the external electric field. It is shown that the increase in the hardness values for a particular system in the presence of external field does not necessarily imply that the reactivity of the system would be deactivated or vice versa.

1 aKar, Rahul1 aChandrakumar, K., R. S.1 aPal, Sourav uhttps://library.ncl.res.in/content/influence-electric-field-global-and-local-reactivity-descriptors-reactivity-and-stability01394nas a2200229 4500008004100000022001400041245009600055210006900151260006800220300001400288490000800302520055300310653002000863653001800883653002900901100001900930700002700949700002400976700001601000700001601016856013201032 2009 eng d a0020-760800aIntermediate hamiltonian hilbert space coupled cluster method: theory and pilot application0 aIntermediate hamiltonian hilbert space coupled cluster method th a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcNOV a2909-29150 v1093 a

The intermediate Hamiltonian state universal (Hilbert-space) coupled-cluster method is presented, using a formalism similar to that developed for the valence universal (Fock-space) approach. The method is expected to be applicable to many states not accessible by traditional multiroot multireference all-order size-extensive approaches. A pilot application to excited states of atomic beryllium shows good convergence and agreement with experiment and full CI values. (C) 2009 Wiley Periodicals, Inc. Int J Quantum Chem 109: 2909-2915, 2009

10acoupled cluster10aHilbert space10aintermediate Hamiltonian1 aEliav, Ephraim1 aBorschevsky, Anastasia1 aShamasundar, K., R.1 aPal, Sourav1 aKaldor, Uzi uhttps://library.ncl.res.in/content/intermediate-hamiltonian-hilbert-space-coupled-cluster-method-theory-and-pilot-application-002126nas a2200217 4500008004100000022001400041245015500055210006900210260007300279300001100352490000800363520128100371653001501652653001401667653001901681653001801700653002501718100001901743700001601762856013001778 2009 eng d a0166-128000aIonization potential and structure relaxation of adenine, thymine, guanine and cytosine bases and their base pairs: a quantification of reactive sites0 aIonization potential and structure relaxation of adenine thymine aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY a96-1020 v9023 a

We present density functional theory (DFT) calculations using B3LYP/6-31++G** method to show relaxation in geometry of base pairs on cation radical formation. The changes in hydrogen bond length and angles show that in the cationic radical form the structure of the base pairs relaxes due to the distribution of charge. According to a recent study. it has been found that, upon excitation hole transfer from base to sugar occurs which results in sugar radical formation and leads to strand breakage 145] [A. Kumar, M.D. Sevilla, J. Phys. Chem. B 110 (2006) 24181]. One hydrogen bond increases, while the other decreases in Adenine-Thymine (AT) base pair and in case of Guanine-Cytosine (GC) base pair. one bond increases and other two decrease. Same is the case with bond angles for both the base pairs. Analysis of the electron density map of Singly Occupied Molecular Orbital (SOMO) reveals that electron is transferred mainly from adenine and guanine bases in the cationic radical formation of AT and CC base pair, respectively. The reactive sites of bases have been analyzed using condensed Fukui functions in a relaxed and frozen core approximation. The effects of relaxation on the reactivity indices are also analyzed. (C) 2009 Elsevier B.V. All rights reserved.

10aBase-pairs10aDNA bases10aFukui function10aH-bond length10aIonization potential1 aMishra, Deepti1 aPal, Sourav uhttps://library.ncl.res.in/content/ionization-potential-and-structure-relaxation-adenine-thymine-guanine-and-cytosine-bases-001450nas a2200169 4500008004100000022001400041245013200055210006900187260007300256300001200329490000800341520073500349100002501084700002601109700001601135856012901151 2010 eng d a0009-261400aInfluence of plane wave cut-off on structural and electronic properties in Sn-BEA and Ti-BEA zeolite water molecule interaction0 aInfluence of plane wave cutoff on structural and electronic prop aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJAN a374-3790 v4843 a

Periodic systems are best described by the pseudo-potential methods. However, the accuracy of its description depends on the cut-off of plane wave basis. This is much more critical in the case of weak interactions, where a clear understanding on the influence of plane wave cut-off on the structural and electronic properties is not readily available in the literature. In the present work, we have taken a metal substituted beta zeolite-H2O complex for understanding this objective. Our studies show that while a lower cut-off of 500 eV is sufficient for the convergence of the structural parameters, description of energy-dependent properties necessitates a high cut-off value. (C) 2009 Elsevier B.V. All rights reserved.

1 aKulkarni, Bhakti, S.1 aKrishnamurty, Sailaja1 aPal, Sourav uhttps://library.ncl.res.in/content/influence-plane-wave-cut-structural-and-electronic-properties-sn-bea-and-ti-bea-zeolite-002344nas a2200169 4500008004100000022001400041245011700055210006900172260007100241300001600312490000800328520165200336100001701988700001602005700002602021856012702047 2013 eng d a1932-744700aInfluence of charge and ligand on the finite temperature behavior of gold clusters: a BOMD study on Au-6 cluster0 aInfluence of charge and ligand on the finite temperature behavio a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT a20982-209900 v1173 a

Conformation and electronic charge on a gold cluster are known to determine its catalytic property. However, little is known on the finite temperature behavior of various gold cluster conformations. Much less is known on the role of charge or a ligand in stabilizing a conformation at finite temperatures. In this work, we have carried out relativistic density functional theory (DFT) based molecular dynamical simulations on neutral and charged Au-6 clusters with an aim of understanding the stability of ground state conformations as a function of charge on the cluster. Our simulations reveal that cationic and anionic Au-6 clusters undergo conformational transitions at 500 K where as neutral Au-6 cluster retains its ground state conformation up to a temperature of 1100 K. In order to look into the factors leading to the stabilization of neutral Au-6 cluster (or destabilization of cationic and anionic Au-6 clusters), structural and electronic properties are analyzed. Factors such as charge redistribution within the atoms and composition of molecular orbitals are seen to contribute towards stronger Au-Au bonds in Au-6(0) thereby stabilizing it considerably. Following the analysis, simulations are also extended to neutral, cationic, and anionic Au-6-COn (n = 1,2) complexes. In the case of CO chemisorbed Au-6 clusters, neutral and negatively charged ground state conformations are stable up to nearly 800 K, while the positively charged Au-6 ground state conformation collapses at room temperature. This work, in short demonstrates how charge or even a ligand can be used to moderate the physical properties of a gold cluster.

1 aManzoor, Dar1 aPal, Sourav1 aKrishnamurty, Sailaja uhttps://library.ncl.res.in/content/influence-charge-and-ligand-finite-temperature-behavior-gold-clusters-bomd-study-au-6-001187nas a2200217 4500008004100000022001400041245008400055210006900139260000800208300001200216490000800228520043300236653003800669653004800707653001600755653003800771100001700809700001600826700001800842856010900860 2013 eng d a0026-897600aInteratomic coulombic decay in (HF)n,(n=2-3) clusters using CAP/EOM-CCSD method0 aInteratomic coulombic decay in HFnn23 clusters using CAPEOMCCSD  cNOV a669-6730 v1123 a

The equation-of-motion coupled-cluster method along with the complex absorbing potential has been applied to study the interatomic Coulombic decay mechanism in hydrogen-bonded clusters. We have applied this method to calculate the lifetime of the F 2s inner-valence ionised state of (HF)(n) (n = 2-3) clusters. The lifetime is found to be very short and decreases substantially with increasing the number of HF monomer.

10acomplex absorbing potential (CAP)10aequation-of-motion coupled-cluster (EOM-CC)10aHF clusters10ainteratomic Coulombic decay (ICD)1 aGhosh, Aryya1 aPal, Sourav1 aVaval, Nayana uhttps://library.ncl.res.in/content/interatomic-coulombic-decay-hfnn2-3-clusters-using-capeom-ccsd-method01630nas a2200181 4500008004100000022001400041245010700055210006900162260007100231300001400302490000700316520092200323100002701245700002001272700001801292700001601310856012201326 2014 eng d a1549-961800aIntermediate hamiltonian fock space multireference coupled cluster approach to core excitation spectra0 aIntermediate hamiltonian fock space multireference coupled clust a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP a3656-36680 v103 a

The Fock space multireference coupled cluster (FSMRCC) method provides an efficient approach for the direct calculation of excitation energies. In intermediate Hamiltonian (IH-FSMRCC) formulation, the method is free from intruder state problems and associated convergence difficulties, even with a large model space. In this paper, we demonstrate that the IH-FSMRCC method with suitably chosen model space can be used for the accurate description of core excitation spectra of molecules, and our results are in excellent agreement with the experimental values. We have investigated the effect of choice of model space on the computed results. Unlike the equation-of-motion (EOM)-based method, the IH-FSMRCC does not require any special technique for convergence and in singles and doubles approximation gives a performance comparable to that of the standard EOMEE-CCSD method, even better in some of the cases.

1 aDutta, Achintya, Kumar1 aGupta, Jitendra1 aVaval, Nayana1 aPal, Sourav uhttps://library.ncl.res.in/content/intermediate-hamiltonian-fock-space-multireference-coupled-cluster-approach-core-002036nas a2200193 4500008004100000022001400041245016500055210006900220260007900289300001100368490000700379520123500386100001801621700002001639700002201659700001801681700001601699856012701715 2015 eng d a2469-992600aImplementation of the Z-vector method in the relativistic-coupled-cluster framework to calculate first-order energy derivatives: Application to the SrF molecule0 aImplementation of the Zvector method in the relativisticcoupledc aONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USAbAMER PHYSICAL SOCcMAR a0305030 v913 a

The molecular dipole moment and magnetic hyperfine-structure constant demand an accurate wave function far from the nucleus and in the near nuclear region, respectively. We, therefore, employ the so-called Z-vector method in the domain of relativistic-coupled-cluster theory to calculate the first-order property of molecular systems in their open-shell ground-state configuration. The implemented method is applied to calculate the molecular dipole moment and parallel component of the magnetic hyperfine-structure constant of the SrF molecule. The results of our calculation are compared with the experimental and other available theoretically calculated values. We are successful in achieving good accordance with the experimental results. The result of our calculation of the molecular dipole moment is in the accuracy of similar to 0.5%, which is clearly an improvement over the previous calculation based on the expectation value method in the four-component coupled-cluster framework [V. S. Prasannaa et al., Phys. Rev. A 90, 052507 (2014)]. Thus, it can be inferred that the Z-vector method can provide an accurate wave function in both the near and far nuclear region, which is evident from our calculated results.

1 aSasmal, Sudip1 aPathak, Himadri1 aNayak, Malaya, K.1 aVaval, Nayana1 aPal, Sourav uhttps://library.ncl.res.in/content/implementation-z-vector-method-relativistic-coupled-cluster-framework-calculate-first-101680nas a2200169 4500008004100000245007800041210006900119260000800188300001600196490000700212520111300219100002001332700001801352700002001370700001601390856010401406 2016 eng d00aInfluence of carbon and phosphorus doping on electronic properties of ZnO0 aInfluence of carbon and phosphorus doping on electronic properti cDEC a12318-123220 v273 aZnO is one of the most promising candidate for photoelectrochemical splitting of water for hydrogen production. To increase the efficiency of ZnO based photoelectrochemical cell, its band-gap and band edges should be tailored to match visible light spectra and water redox potential respectively. In this paper, First-principles density functional theory calculations have been performed to evaluate the effect of non-metal dopants on electronic properties of ZnO. The model structures of X-doped ZnO were constructed using 32-atom 2 x 2 x 2 supercell of wurtzite ZnO with one O atom replaced with X (carbon C, phosphorus P). With respect to the electronic band structure, C (2p), P (3p) states are located above the valence band maximum of ZnO and mixing of these states is feeble to produce significant band gap narrowing. Doping of these non-metals dopants helps in the creation of isolated states which enhances visible light absorption of ZnO. Our theoretical calculations are consistent with the experimental results of C (P) doped ZnO and fully explains its visible light activity on non-metal doping.1 aSharma, Vidhika1 aPrasad, Mohit1 aJadkar, Sandesh1 aPal, Sourav uhttps://library.ncl.res.in/content/influence-carbon-and-phosphorus-doping-electronic-properties-zno01653nas a2200217 4500008004100000022001400041245014100055210006900196260000800265300001300273490000800286520083500294653002501129653004701154653001501201653003801216100001701254700001601271700001801287856013001305 2021 eng d a0026-897600aInteratomic Coulombic decay in Neon-Helium cluster: a complex absorbing potential based equation-of-motion coupled cluster investigation0 aInteratomic Coulombic decay in NeonHelium cluster a complex abso cMAY ae18843000 v1193 a

The interatomic Coulombic decay (ICD) of the Ne(2s(-1)) and Ne(2s(-1)2p(-1)) states in neon-helium dimer is studied using highly accurate complex absorbing potential based equation-of-motion coupled cluster (CAP-EOMCC) method. The ICD decay process for the Ne(2s(-1)) state in neon-helium dimer is closed at its equilibrium bond distance. However, the decay channel is open at large bond distance of 6.2 angstrom. The decay channel for the double ionised Ne(2s(-1)2p(-1)) state is open at 3.46 angstrom. From our calculations, we have noticed that the decay rate of Ne(2s(-1)2p(-1)) state in neon-helium dimer is four times faster compared to the Ne(2s(-1)) state. We have also investigated how the decay rate of Ne(2s(-1)) state in neon-helium cluster varies in the presence of different helium environment. [GRAPHICS] .

10adouble ionised state10aequation-of-motion coupled cluster (EOMCC)10aHe droplet10ainteratomic Coulombic decay (ICD)1 aGhosh, Aryya1 aPal, Sourav1 aVaval, Nayana uhttps://library.ncl.res.in/content/interatomic-coulombic-decay-neon-helium-cluster-complex-absorbing-potential-based-equation