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Shuo Li J. R. Fried Jeremy Sauer John Colebrook Douglas S. Dudis 《International journal of quantum chemistry》2011,111(12):3212-3229
Quantum mechanics (QM) calculations, molecular dynamics (MD) simulations using the condensed‐phase optimized molecular potentials for atomistic simulation studies (COMPASS) force field, and the atom‐centered density matrix propagation (ADMP) approach have been used to investigate properties of phosphoric acid (PA). QM using B3LYP/6‐31++G(d,p) density functional theory were used to calculate gas‐phase proton affinities and interaction energies of PA and its derivatives. Detailed single coordinate driving, followed by quadratic synchronous transit optimization was used to determine energy barriers for different proton transfer (PT) pathways. Determined energy barrier heights in ascending order are (unit: kJ/mol): H3O+→H3PO4 (0); H4P2O7→H3PO4 (2.61); H3PO4→H2PO (5.31); H4PO→H3PO4 (~7.33); H3PO4→H4P2O7/H3PO4→H3PO4 (15.99); H4P2O7→H2O (28.61); H3PO4→H2O (47.14). The COMPASS force field was used to study condensed‐phase properties of PA. Good agreement between experimental data and MD results including density, radial distribution functions, and self‐diffusion coefficient at different temperatures provides validation of the COMPASS force field for PA. Finally, preliminary ADMP studies on a cluster of three PA molecules shows that the ADMP approach can reasonably describe the PT and self‐dissociation processes in PA. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 相似文献
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Reactivity of molecular oxygen with aluminum clusters: Density functional and Ab Initio molecular dynamics simulation study 下载免费PDF全文
Selvarengan Paranthaman Jiwon Moon Kiryong Hong Jeongho Kim Dong Eon Kim Joonghan Kim Tae Kyu Kim 《International journal of quantum chemistry》2016,116(7):547-554
Dissociative adsorption of molecular oxygen (O2) on aluminum (Al) clusters has attracted much interest in the field of surface science and catalysis, but theoretical predictions of the reactivity of this reaction in terms of barrier height is still challenging. In this regard, we systematically investigate the reactivity of O2 with Al clusters using density functional theory (DFT) and atom‐centered density matrix propagation (ADMP) simulations. We also calculate potential energy surfaces (PESs) of the reaction between O2 and Al clusters to estimate the barrier energy of this reaction. The M06‐2X functional gives the barrier energy in agreement with the one calculated by coupled cluster singles and doubles with perturbed triples (CCSD(T)) while the TPSSh functional significantly underestimates the barrier height. The ADMP simulation using the M06‐2X functional predicts the reactivity of O2 with the Al cluster in agreement with the experimental findings, that is, singlet O2 readily reacts with Al clusters but triplet O2 is less reactive. We found that the ability of a DFT functional to describe the charge transfer appropriately is critical for calculating the barrier energy and the reactivity of the reaction of O2 with Al clusters. The M06‐2X functional is relevant for investigating chemical reactions involving Al and O2. © 2016 Wiley Periodicals, Inc. 相似文献
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Jessica L. Kroger Joel R. Fried Adam A. Skelton 《International journal of quantum chemistry》2013,113(1):63-70
Density functional theory (DFT) calculations, including the ab initio molecular dynamics method, atom‐centered density matrix propagation (ADMP), were used to investigate the hydrolysis reaction of a dichlorophosphazene trimer. The model trimer, intermediate structures and the product of the first step of hydrolysis, were optimized using DFT with the B3LYP density functional, followed by a 600 fs ADMP simulation. Natural bond order analysis (NBO) was used to determine atomic charges and occupancy of the bond orbitals and the lone pair orbitals of the molecule at various points along the simulation pathway. The simulation successfully shows dissociation of the trimer backbone into two distinct product molecules, shown through both increasing separation of the product units and through the more thorough NBO analysis of the bond orbitals. © 2012 Wiley Periodicals, Inc. 相似文献
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