22 documents found, page 1 of 3

Ab initio potentials: From CBS extrapolation to globalness to riddles in the ch...

A Direct Evaluation of the Partition Function and Thermodynamic Data for Water ...

Texto completo: acesso restrito. p. 6193–6200; Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-01-20T12:34:11Z No. of bitstreams: 1 Frederico V. Prudente.pdf: 89075 bytes, checksum: 0039732a0c47b4e38ee8547b044767c7 (MD5); Made available in DSpace on 2014-01-20T12:34:11Z (GMT). No. of bitstreams: 1 Frederico V. Prudente.pdf: 89075 bytes, checksum: 0039732a0c47b4e38ee8547b044767c7 (MD5) Previous issu...

Photoinduced coupled twisted intramolecular charge transfer and excited-state p...

We discuss theoretically the geometric and electronic structure properties of the thiazolidinedione derivative A and its hydrogen-bonded complex in dimethylformamide (DMF) solution in the S0 and S1 states. To gain insight into the photoinduced coupled excited-state proton transfer (ESPT) and twisted intramolecular charge transfer (TICT) associated with intermolecular hydrogen bonding, the potential energy profi...

Accurate Potential Energy Surfaces and Beyond: Chemical Reactivity, Binding, Lo...

Beginning with the seminal paper of Born and Oppenheimer (BO) [1] in 1927, the concept of the potential energy surface (PES) plays a critical role in the description, simulation, and modeling of molecular systems. It provides the basis [2] for understanding the processes associated with the nuclear motions in molecules. By going beyond the characteristic stationary points and barriers, full dimensional, accurat...

Vibrational Relaxation of Highly Vibrationally Excited O3 in Collisions with OH

We report a theoretical study of highly excited O3 in collisions with vibrationally cold OH. Special emphasis is placed on initial vibrational energies of O3 between 9 and 21 kcal mol−1. All calculations have employed the quasiclassical trajectory method and the realistic double many-body expansion potential energy surface for HO4(2A). Many aspects of the title relaxation process are presented. The results indi...

Application of renormalized coupled-cluster methods to potential function of water

Abstract The goal of this paper is to examine the performance of the conventional and renormalized single-reference coupled-cluster (CC) methods in calculations of the potential energy surface of the water molecule. A comparison with the results of the internally contracted multi-reference configuration interaction calculations including the quasi-degenerate Davidson correction (MRCI(Q)) and the spectroscopical...

HN2(2A‘) Electronic Manifold. II. Ab Initio Based Double-Sheeted DMBE Potential...

A double-sheeted double many-body expansion potential energy surface is reported for the coupled 12A‘/22A‘ states of HN2 by fitting about 6000 ab initio energies. All crossing seams are described to their full extent on the basis of converged results. The lowest adiabatic sheet is fitted with a rmsd of 0.8 kcal mol-1 with respect to the calculated energies up to 100 kcal mol-1 above the absolute minimum, and th...

HN2(2A‘) Electronic Manifold. I. A Global ab Initio Study of First Two States

A detailed ab initio multireference configuration interaction calculation with a standard aug-cc-pVTZ basis set is reported for the 12A‘ and 22A‘ states of the title system. The aim is to establish the dissociation scheme of all channels, while revealing the 22A‘/32A‘ seam of conical intersections consistent with the crossings in the diatomic fragments. An ab initio mapping of linear NNH and T-shaped and linear...

Variational transition-state theory study of the atmospheric reaction OH + O3 →...

We report variational transition-state theory calculations for the OH + O3rarr HO2 + O2 reaction based on the recently reported double many-body expansion potential energy surface for ground-state HO4 [Chem Phys Lett 2000, 331, 474]. The barrier height of 1.884 kcal mol-1 is comparable to the value of 1.77-2.0 kcal mol-1 suggested by experimental measurements, both much smaller than the value of 2.16-5.11 kcal ...

A Quantum Wave Packet Dynamics Study of the N(2D) + H2 Reaction

We report a dynamics study of the reaction N(2D) + H2 (v=0, j=0−5) → NH + H using the time-dependent quantum wave packet method and a recently reported single-sheeted double many-body expansion potential energy surface for NH2(12A‘‘) which has been modeled from accurate ab initio multireference configuration-interaction calculations. The calculated probabilities for (v=0, j=0−5) are shown to display resonance s...