02881nas a2200229   4500008004100000022001400041245012700055210006900182260007300251300001200324490000700336520200400343653002202347653002102369653002102390653002202411653002902433100001902462700002302481700001602504856013102520       2008                        eng d  a0927-025600aFirst principles calculations of thermal, equations of state and thermodynamical properties of MgH2 at finite temperatures0 aFirst principles calculations of thermal equations of state and   aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY  a510-5160 v423 a<p>We present the first principles calculations of the thermodynamical properties of magnesium hydride (MgH2) over a temperature range of 0-1000 K. The phonon dispersions are determined within the density functional framework and are used to calculate the free energy of MgH2 within the quasiharmonic approximation (QHA) at each cell volume and temperature T. Using the free energies the thermal equation of state (EOS) is derived at several temperatures. From the thermal EOS structural parameters such as the equilibrium bell volume (V-0) and elastic properties, namely, bulk modulus (K-0) and its pressure derivative (K-0(')) are computed. The free energies are also used to calculate various thermodynamical properties within QHA. These include internal energy E, entropy S, specific heat capacity at constant pressure C-P, thermal pressure P-thermal(V,T) and volume thermal expansion Delta V/V (%). The good agreement of calculated values of S and Cp with experimental data exhibits that QHA can be used as a tool for calculating the thermodynamical properties of MgH2 over a wide temperature range. P-thermal(V,T) increases strongly with T at all the volumes but it is a slowly varying function of volume for T = 298-500 K. According to Karki [B.B. Karki, Am. Miner. 85 (2000) 1447] such volume based variations can be neglected and so it is possible to estimate the thermal EOS only with the knowledge of the measured P-thermal(V,T) versus temperature at ambient pressure and isothermal compression data at ambient temperature. Temperature dependence of Delta V/V(%) shows that V-0 increased with increase in temperature. However, the percentage decrease in K-0 superseded this percentage increase in V-0 even at temperatures moderately higher than 298 K. Therefore, we suggest application of temperature (T &gt; 298 K) as an approach to enhance the hydrogen storage capacity of MgH2 because of its better compressibility at these temperatures. (C) 2007 Elsevier B.V. All rights reserved.</p>10aequation of state10aHydrogen storage10alattice dynamics10amagnesium hydride10aThermodynamic properties1 aKelkar, Tuhina1 aKanhere, Dilip, G.1 aPal, Sourav  uhttps://library.ncl.res.in/content/first-principles-calculations-thermal-equations-state-and-thermodynamical-properties-mgh2-001757nas a2200181   4500008004100000022001400041245016900055210006900224260012500293300001100418490000800429520092800437100001601365700002801381700001801409700001601427856013201443       2009                        eng d  a0021-960600aFirst- and second-order electrical properties computed at the FSMRCCSD level for excited states of closed-shell molecules using the constrained-variational approach0 aFirst and secondorder electrical properties computed at the FSMR  aCIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScJUL  a0241020 v1313 a<p>Fock space multireference coupled-cluster (FSMRCC) method emerged as an efficient tool to describe the electronic structure of nearly degenerate cases. Development of linear response has been one of the challenging problems in FSMRCC due to the multiple-root nature of the effective Hamiltonian. A response from any of the roots would span the space for getting the properties. Hence, all roots perturbed by the external field would proliferate the excited states. We recently developed the FSMRCC method for the efficient evaluation of analytic response properties using a constrained variation approach. In this paper, we present analytic dipole moments and polarizabilities of H2O, O-3, and CH+ molecules in low-lying excited states along with brief discussion of singlet triplet decoupling of (1,1) sector of FSMRCC resulting from spin adaptation. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3167796]</p>1 aBag, Arijit1 aManohar, Prashant, Uday1 aVaval, Nayana1 aPal, Sourav  uhttps://library.ncl.res.in/content/first-and-second-order-electrical-properties-computed-fsmrccsd-level-excited-states-closed-001191nas a2200205   4500008004100000022001400041245009000055210006900145260009200214300001800306490000800324520041200332653002000744653002400764653002300788653001500811653002000826100001600846856012300862       2010                        eng d  a0026-897600aFock space multi-reference coupled-cluster method for energies and energy derivatives0 aFock space multireference coupledcluster method for energies and  a4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLANDbTAYLOR & FRANCIS LTDcOCT  aPII 9279617140 v1083 a<p>In this article, the development of Fock space multi-reference coupled-cluster method is reviewed. Molecular applications of the method for excitation and ionisation energies which took place at Quantum Theory Project have been discussed. Later developments of the method for energy derivatives have been presented along with pilot applications of molecular properties of radicals and excited states.</p>10acoupled-cluster10adifference energies10aenergy derivatives10aFock space10aMulti-reference1 aPal, Sourav  uhttps://library.ncl.res.in/content/fock-space-multi-reference-coupled-cluster-method-energies-and-energy-derivatives-000844nas a2200181   4500008004100000022001400041245011600055210006900171260007100240300001600311490000800327520014800335100002400483700002600507700001900533700001600552856009400568       2011                        eng d  a1932-744700aFinite temperature behavior of gas phase neutral Au-n (3 <= n <= 10) clusters: a first principles investigation0 aFinite temperature behavior of gas phase neutral Aun 3 n 10 clus  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP  a17278-172850 v1153 a<p>{Relativistic density functional theory (DFT) based molecular dynamical simulations are performed on gold clusters with 3-10 atoms (Au-n</p>1 aDe, Himadri, Sekhar1 aKrishnamurty, Sailaja1 aMishra, Deepti1 aPal, Sourav  uhttps://library.ncl.res.in/content/finite-temperature-behavior-gas-phase-neutral-au-n-3-001859nas a2200229   4500008004100000022001400041245010400055210006900159260007300228300001200301490000800313520098400321653001801305653004001323653003001363653002201393653002501415100002401440700002601464700001601490856012301506       2012                        eng d  a0920-586100aFirst principle investigation on the thermal stability of a golden fullerene: a case study of Au-320 aFirst principle investigation on the thermal stability of a gold  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC  a106-1090 v1983 a<p>Structural and electronic properties of Au-32 cluster are analyzed using relativistic density functional theory (DFT) based methods. Further, DFT based molecular dynamical (MD) simulations are performed on Au-32 golden fullerene with an aim of understanding its thermal stability at various working temperatures. Various conformations being populated at different temperatures of a cluster are analyzed. The study shows that the ground state icosahedral conformation is stable only up to 300 K and structure remains in a hollow conformation only up to 400 K. This clearly explains the reasons for failure by experimentalists in trapping the unique fullerene conformation in spite of the theoretical predictions of it being a very stable one. The above MD study also indicates that the bare fullerene Au-32 cluster (without any stabilizing ligands) can be used for potential catalytic applications only around room temperatures. (C) 2012 Elsevier B. V. All rights reserved.</p>10aAu-32 cluster10aBorn-Oppenheimer molecular dynamics10aDensity functional theory10aGolden fullerenes10aRelativistic effects1 aDe, Himadri, Sekhar1 aKrishnamurty, Sailaja1 aPal, Sourav  uhttps://library.ncl.res.in/content/first-principle-investigation-thermal-stability-golden-fullerene-case-study-au-32-000637nas a2200157   4500008004100000245012300041210006900164260000800233300001200241490000800253100002600261700002700287700001800314700001600332856013100348       2012                        eng d00aFock-space multi-reference coupled-cluster response with the effect of triples on dipole moment of ClO and SF radicals0 aFockspace multireference coupledcluster response with the effect  cJAN  a223-2320 v1241 aRavichandran, Lalitha1 aBhattacharya, Debarati1 aVaval, Nayana1 aPal, Sourav  uhttps://library.ncl.res.in/content/fock-space-multi-reference-coupled-cluster-response-effect-triples-dipole-moment-clo-and-sf01243nas a2200205   4500008004100000022001400041245007900055210006900134260006700203300001400270490000800284520045300292653004600745653005300791653002000844100002700864700001800891700001600909856011200925       2013                        eng d  a0020-760800aFock space multireference coupled cluster theory: study of shape resonance0 aFock space multireference coupled cluster theory study of shape   a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcJUN  a1690-16950 v1133 a<p>The complex absorbing potential along with correlated independent particle potential (CIP) Fock space multireference coupled cluster method is used for the study of resonances. We have studied shape resonance of e(-) - F-2, e(-) - N2O and e(-) -CO molecules. In particular, we have studied e(-) - F-2 scattering at different bond lengths to know whether F-2(-) is bound at the equilibrium bond length of F-2. (C) 2013 Wiley Periodicals, Inc.</p>10acorrelated independent particle potential10aFock-space multireference coupled cluster theory10ashape resonance1 aBhattacharya, Sumantra1 aVaval, Nayana1 aPal, Sourav  uhttps://library.ncl.res.in/content/fock-space-multireference-coupled-cluster-theory-study-shape-resonance-0