@article { ISI:000254309400007, title = {Shape resonance in electron molecule scattering using coupled cluster method}, journal = {Indian Journal of Physics and Proceedings of the Indian Association for the Cultivation of Science}, volume = {81}, number = {10}, year = {2007}, month = {OCT}, pages = {1061-1067}, publisher = {INDIAN ASSOC CULTIVATION SCIENCE}, type = {Article}, address = {INDIAN J PHYSICS, JADAVPUR, KOLKATA 700 032, INDIA}, abstract = {

The Fock space multi-reference coupled-cluster (FSMRCC) method along with the complex absorbing potential (CAP) is used for the study of the shape resonance energy and width in an electron molecule collision. We study the shape resonances in e(-) -H2CO and e(-) -CO.

}, keywords = {electron-molecule scattering, multi-reference coupled-cluster}, issn = {0973-1458}, author = {Pal, Sourav and Vaval, Nayana and Sajeev, Y.} } @proceedings {42678, title = {On some aspects of fock-space multi-reference coupled-cluster singles and doubles energies and optical properties}, volume = {11}, year = {2010}, month = {APR}, pages = {375-393}, publisher = {Springer}, address = {Netherlands}, author = {Manohar, Prashant Uday and Shamasundar, K. R. and Bag, Arijit and Vaval, Nayana and Pal, Sourav} } @article { ISI:000293192100022, title = {Size- and shape-sensitive reactivity behavior of Al-n(n=2-5, 13, 30, and 100) clusters toward the N-2 molecule: a first-principles investigation}, journal = {Journal of Physical Chemistry C}, volume = {115}, number = {30}, year = {2011}, month = {AUG}, pages = {14615-14623}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Reactivity of aluminum clusters has been found to exhibit size-sensitive variations. N-2 reduction is a hard process, and its dissociation on the Al surface is one of the few chemical methods available under nonhazardous conditions. In this context, we attempt to understand the adsorption behavior of N-2 molecules as a function of varying size and shape of Al clusters using a Density Functional Theory (DFT) based method. During the complex formation, various N-2 adsorption modes are examined. The results clearly demonstrate that, while the interaction energy does not vary with respect to the cluster size, shape of the cluster is highly contributive toward the chemisorption (a prerequisite for the reactivity) of the N-2 molecule. The underlying electronic and structural factors influencing the adsorption of N-2 molecules on the Al clusters are analyzed with the help of the Electron Localization Function (ELF) and Frontier Molecular Orbitals. As an illustration, the activation barrier calculations on various Al-13 conformations are calculated, and results confirm the experimental propositions that high-energy structures (depending upon their geometrical and electronic orientation) are more favorable for N-2 reduction.

}, issn = {1932-7447}, doi = {10.1021/jp203452a}, author = {Kulkarni, Bhakti S. and Krishnamurty, Sailaja and Pal, Sourav} } @article { ISI:000307748700004, title = {Scandium-decorated MOF-5 as potential candidates for room-temperature hydrogen storage: a solution for the clustering problem in MOFs}, journal = {Journal of Physical Chemistry C}, volume = {116}, number = {33}, year = {2012}, month = {AUG}, pages = {17336-17342}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Transition-metal-based systems show promising binding energy for hydrogen storage but suffer from clustering problem. The effect of light transition metal (M = Sc, Ti) decoration, boron substitution on the hydrogen storage properties of MOF-5, and clustering problem of metals has been investigated using ab initio density, functional theory. Our results of solid-tate calculations reveal that whereas Ti clusters strongly Sc atoms do not suffer from this problem when decorating MOF-5. Boron substitution on metal-decorated MOF-5 enhances the interaction energy of both the metals with MOF-5. Sc-decorated MOF-5 shows a hydrogen storage capacity of 5.81 wt \% with calculated binding energies of 20-40 kJ/mol, which ensures the room-teniperature applicability of this hydrogen storage material.

}, issn = {1932-7447}, doi = {10.1021/jp302852h}, author = {Dixit, Mudit and Maark, Tuhina Adit and Ghatak, Kamalika and Ahuja, Rajiv and Pal, Sourav} } @article { ISI:000323177900012, title = {Study of interatomic coulombic decay of Ne(H2O)(n) (n=1,3) clusters using equation-of-motion coupled-cluster method}, journal = {Journal of Chemical Physics}, volume = {139}, number = {6}, year = {2013}, month = {AUG}, pages = {Article No. 064112}, publisher = {AMER INST PHYSICS}, address = {CIRCULATION \& FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA}, abstract = {

Interatomic Coulombic decay (ICD) is an efficient and ultrafast radiationless decay mechanism which can be initiated by removal of an electron from the inner-valence shell of an atom or molecule. Generally, the ICD mechanism is prevailed in weakly bound clusters. A very promising approach, known as CAP/EOM-CC, consists of the combination of complex absorbing potential (CAP) with the equation-of-motion coupled-cluster (EOM-CC) method, is applied for the first time to study the nature of the ICD mechanism. We have applied this technique to determine the lifetime of an auto-ionized, inner-valence excited state of the NeH2O, Ne(H2O)(2), and Ne(H2O)(3) systems. The lifetime is found to be very short and decreases significantly with the number of neighboring water molecules. (C) 2013 AIP Publishing LLC.

}, issn = {0021-9606}, doi = {10.1063/1.4817966}, author = {Ghosh, Aryya and Pal, Sourav and Vaval, Nayana} } @article { ISI:000332188200009, title = {Structure, stability, and properties of the trans peroxo nitrate radical: the importance of nondynamic correlation}, journal = {Journal of Physical Chemistry A}, volume = {118}, number = {8}, year = {2014}, month = {FEB}, pages = {1350-1362}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

We report a comparative single-reference and multireference coupled-cluster investigation on the structure, potential energy surface, and IR spectroscopic properties of the trans peroxo nitrate radical, one of the key intermediates in stratospheric NOx chemistry. The previous single-reference ab initio studies predicted an unbound structure for the trans peroxo nitrate radical. However, our Fock space multireference coupled-cluster calculation confirms a bound structure for the trans peroxo nitrate radical, in accordance with the experimental results reported earlier. Further, the analysis of the potential energy surface in FSMRCC method indicates a well-behaved minima, contrary to the shallow minima predicted by the single-reference coupled-cluster method. The harmonic force field analysis, of various possible isomers of peroxo nitrate also reveals that only the trans structure leads to the experimentally observed IR peak at 1840 cm(-1). The present study highlights the critical importance of nondynamic correlation in predicting the structure and properties of high-energy stratospheric NOx radicals.

}, issn = {1089-5639}, doi = {10.1021/jp409218c}, author = {Dutta, Achintya Kumar and Dar, Manzoor and Vaval, Nayana and Pal, Sourav} } @conference { ISI:000354845400033, title = {Study of molecular vibration by coupled cluster method: bosonic approach}, booktitle = {Proceedings of the International Conference of Computational Methods in Sciences and Engineering 2010 (ICCMSE-2010)}, series = {AIP Conference Proceedings}, volume = {1642}, year = {2015}, note = {International Conference of Computational Methods in Sciences and Engineering (ICCMSE), Kos, GREECE, OCT 03-08, 2010}, month = {FEB}, pages = {227-230}, publisher = {European Soc Computat Methods Sci, Engn \& Technol}, organization = {European Soc Computat Methods Sci, Engn \& Technol}, address = {2 Huntington Quadrangle, STE 1NO1, Melville, NY 11747-4501 USA}, abstract = {

The vibrational coupled cluster method in bosonic representation is formulated to describe the molecular anharmonic vibrational spectra. The vibrational coupled cluster formalism is based on Watson Hamiltonian in normal coordinates. The vibrational excited states are described using coupled cluster linear response theory (CCLRT). The quality of the coupled cluster wave function is analyzed. Specifically, the mean displacement values of the normal coordinates and expectation values of the square of the normal coordinates of different vibrational states are calculated. A good agreement between the converged full CI results and coupled cluster results is found for the lower lying vibrational states.

}, keywords = {CCLRT, Expectation values, Watson Hamiltonian}, isbn = {978-0-7354-1282-8}, issn = {0094-243X}, doi = {10.1063/1.4906658}, author = {Banik, Subrata and Pal, Sourav and Prasad, M. Durga}, editor = {Simos, TE and Maroulis, G} } @article { ISI:000361649900037, title = {Systematic comparison of DFT and CCSD dipole moments, polarizabilities and hyperpolarizabilities (vol 635, pg 168, 2015)}, journal = {Chemical Physics Letters}, volume = {636}, year = {2015}, month = {SEP}, pages = {228-229}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, issn = {0009-2614}, doi = {10.1016/j.cplett.2015.08.034}, author = {Karne, Anagha S. and Vaval, Nayana and Pal, Sourav and Vasquez-Perez, Jose M. and Koester, Andreas M. and Calaminici, Patrizia} } @article { ISI:000362239300030, title = {Systematic comparison of DFT and CCSD dipole moments, polarizabilities and hyperpolarizabilities}, journal = {Chemical Physics Letters}, volume = {635}, year = {2015}, month = {AUG}, pages = {168-173}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A comparative study of dipole moments, polarizabilities and hyperpolarizabilities of 16 different molecules is performed employing two completely different theoretical approaches namely, density functional theory (DFT) and coupled cluster singles and doubles (CCSD). Both methods include electron correlation. The CCSD method is more accurate but highly expensive. DFT with auxiliary density allows non-iterative solutions which is computational advantage and useful for large molecules. Dipole moments and polarizability calculations from DFT are in very good agreement with CCSD calculations. However, negative hyperpolarizability values from DFT differ significantly from their CCSD counterparts, whereas positive hyperpolarizabilities show reasonable agreement between these methodologies. (C) 2015 Elsevier B.V. All rights reserved.

}, issn = {0009-2614}, doi = {10.1016/j.cplett.2015.06.046}, author = {Karne, Anagha S. and Vaval, Nayana and Pal, Sourav and Vasquez-Perez, Jose M. and Koester, Andreas M. and Calaminici, Patrizia} } @article {42621, title = {Search for parity and time reversal violating effects in HgH: relativistic coupled-cluster study}, journal = {Journal of Chemical Physics}, volume = {144}, year = {2016}, month = {MAR}, pages = {Article No. 124307}, abstract = {

The high effective electric field (E-eff) experienced by the unpaired electron in an atom or a molecule is one of the key ingredients in the success of electron electric dipole moment (eEDM) experiment and its precise calculation requires a very accurate theory. We, therefore, employed the Z-vector method in the relativistic coupled-cluster framework and found that HgH has a very large E-eff value (123.2 GV/cm) which makes it a potential candidate for the next generation eEDM experiment. Our study also reveals that it has a large scalar-pseudoscalar (S-PS) P, T-violating interaction constant, W-s = 284.2 kHz. To judge the accuracy of the obtained results, we have calculated parallel and perpendicular magnetic hyperfine structure (HFS) constants and compared with the available experimental values. The results of our calculation are found to be in nice agreement with the experimental values. Therefore, by looking at the HFS results, we can say that both E-eff and W-s values are also very accurate. Further, We have derived the relationship between these quantities and the ratio which will help to get model independent value of eEDM and S-PS interaction constant. (C) 2016 AIP Publishing LLC.

}, doi = {10.1063/1.4944673}, author = {Sasmal, Sudip and Pathak, Himadri and Nayak, Malaya K. and Vaval, Nayana and Pal, Sourav} } @article {45638, title = {Strategic Preparation of Efficient and Durable NiCo Alloy Supported N-Doped Porous Graphene as an Oxygen Evolution Electrocatalyst: A Theoretical and Experimental Investigation}, journal = {Advanced Materials Interfaces}, volume = {3}, year = {2016}, month = {OCT }, pages = {1600532}, type = {Article}, abstract = {

Development of an efficient and durable water splitting electrocatalyst holds a great commitment for the future energy devices. The real application of oxygen evolution reaction (OER) catalysts mainly suffers from sluggish kinetics and high overpotential except for the Ir and Ru-based systems. However, the high cost and vulnerability of the Ir and Ru metals are the main hostiles to use them for marketization. Herein, a high-performance OER electrocatalyst consisting of NiCo alloy nanoparticles supported on high surface area N-doped porous graphene (NiCo/pNGr(75: 25)) is reported. The importance of the doped-N for achieving the uniform dispersion-cum-effective interaction of the size controlled NiCo alloy nanoparticles has been explicitly investigated by transmission electron microscopy, X-ray diffraction, X-ray photo electron spectroscopy, Raman, density functional theory (DFT) calculations, etc. The electrochemical analysis of NiCo/pNGr(75: 25) shows an overpotential of approximate to 260 mV at 10 mA cm(-2) with a smaller Tafel slope of approximate to 87 mV dec(-1) and long catalytic durability. DFT calculations are done to check the interaction between the NiCo alloy nanoparticles and the defective sites of pNGr and also with the doped-N, which could be attained for maintaining long catalytic durability. Furthermore, NiCo/pNGr(75: 25) is used as an OER catalyst to fabricate an electrolyzer, which works at very low potential of 1.5 V in 1 M KOH.

}, issn = {2196-7350}, doi = {10.1002/admi.201600532}, author = {Singh, Santosh K. and Kumar, Deepak and Dhavale, Vishal M. and Pal, Sourav and Kurungot, Sreekumar} } @article {45378, title = {Specificity of amino acid-aluminum cluster interaction and subsequent oxygen activation by the above complex}, journal = {Journal of Physical Chemistry C }, volume = {122}, year = {2018}, month = {DEC}, pages = {28310-28323}, type = {Article}, abstract = {Amino acid aluminum cluster complex has been shown to be a promising oxygen molecule activator and has the potential to dissociate O-O bond on the cluster surface. The study of the complex also reveals specificity of amino acid to aluminum cluster in the above complex, which can be used in the detection of amino acid. The results have been obtained by the density functional theory at the B3LYP/6-311++g(d,p) level of calculation.}, issn = { 1932-7447}, doi = { 10.1021/acs.jpcc.8b08396}, author = {Samanta, Bipasa and Sengupta, Turbasu and Pal, Sourav} } @article {46959, title = {Shape resonance of sulphur dioxide anion excited states using the CAP-CIP-FSMRCCSD method}, journal = {Molecular Physics}, volume = {118}, year = {2020}, month = {AUG }, type = {Article}, abstract = {

We have studied the shape resonance of excited states of sulphur dioxide (SO2) anion by using the correlated independent particle Fock space multi-reference coupled cluster (CAP-CIP-FSMRCCSD) method augmented by complex absorption potential. These resonant states have been trapped experimentally in recent years by electron collision. In particular, we have investigated e(-)-SO2 scattering and computed the negative-ion resonance states of the anion responsible for the two resonances around 4.45 and 6.56 eV and compared the results with the existing experimental observations. From the computational results using the CAP-CIP-FSMRCCSD method, it has been observed that both the resonances near 4.45 and 6.56 eV result from A(1) symmetries. [GRAPHICS] .

}, keywords = {CAP augmented correlated independent particle (CAP-CIP-FSMRCCSD), complex absorption potential (CAP), coupled cluster, Fock space multireference coupled cluster (FSMRCCSD), shape resonance}, issn = {0026-8976}, doi = {10.1080/00268976.2020.1726521, Early Access Date = FEB 2020}, author = {Basumallick, Suhita and Bhattacharya, Sumantra and Jana, Irina and Vaval, Nayana and Pal, Sourav} }