Potential energy hydrogen fluoride

Michael, D. W., Dykstra, C. E., and Lisy, J. M., Changes in the electronic structure and vibrational potential of hydrogen fluoride upon dimerization A well-correlated (HF) potential energy surface, J. Chem. Phys. 81, 5998-6006 (1984). 

D. W. Michael, C. E. Dykstra, and J. M. Lisy, ]. Chem. Phys., 81,5998 (1984). Changes in the Electronic Structure and Vibrational Potential of Hydrogen Fluoride Upon Dimerization A Well-Correlated (HF)2 Potential Energy Surface. 

Hydrogen abstraction reactions potential surfaces for, 25-26,26,41 resonance structures for, 24 Hydrogen atom, 2 Hydrogen bonds, 169,184 Hydrogen fluoride, 19-20, 20,22-23 Hydrogen molecules, 15-18 energy of, 11,16,17 Hamiltonian for, 4,15-16 induced dipoles, 75,125 lithium ion effect on, 12... 

For simplicity we shall assume the fluoride ion to consist of the nucleus, two K electrons very close to it, and eight L21 L22 electrons for as can be seen from the representation of the sodium ion in fig. 3 the Lu electrons show nearly the same distribution along r as the L21 L22 electrons. The potential energy of a hydrogen nucleus at the distance R from the fluorine nucleus is then... 

Other structural analyses of crystals in which the bifluoride is present are listed in Table 7. One compound, p-toluidinium fluoride [C7H,oN ][HF2 ], is worthy of further comment. The first X-ray diffraction study reported a symmetrical anion (Denne and MacKay, 1971), but a later analysis showed that the proton was not centred between the two fluorines and 7 f h values were 102.5 and 123.5 pm (Williams and Schneemeyer, 1973). This can be explained not by a double minimum potential energy well but by asymmetry due to other forces, such as secondary hydrogen bonding between one end of the bifluoride anion and the N—H group of the cation. An alternative explanation attributes the asymmetry of the bifluoride hydrogen bond to an unsymmetrical crystal field caused by the cation (Ostlund and Bellenger, 1975). 

The mechanistic borderline between E2 and ElcB mechanisms has been studied under various conditions.1,2 The mechanism of the elimination reaction of 2-(2-fluoroethyl)-1-methylpyridinium has been explored explored by Car-Parrinello molecular dynamics in aqueous solution.3 The results indicated that the reaction mechanism effectively evolves through the potential energy region of the carbanion the carbon-fluoride bond breaks only after the carbon-hydrogen bond. 

One of the early applications of molecular electrostatic potentials was in relation to hydrogen bonding. The Fm n (most negative potentials) were found to be effective in identifying sites at which hydrogen bonds would be accepted [16,89-91]. Furthermore, Kollman et al. [89] showed that the calculated energy of the interaction between hydrogen fluoride and a series of acceptors correlates well with the value of V(r) at a fixed distance from the latter. 

A. E. Barton and B. J. Howard, Faraday Discuss. Chem. Soc., 73,45 (1982). An Intermolecular Potential-Energy Surface for Hydrogen Fluoride Dimer. 

As demonstrated in our recent works [33-35], the CASCCSD wave function constructed in the above-described way provides in all studied cases a very accurate description of the potential energy curve (PEC) in comparison with FCI. Let us, for example, show in more details how the method performs in the case of the dissociation of the hydrogen fluoride (FH) molecule. The calculations have been performed with the standard valence double-zeta (DZV) basis set (implemented in GAMESS package [36]). The results are presented in Table 3.2. As one can see in Table 3.2, the differences between the CAS(2,2)CCSD and FCI energies are almost constant and small for all the PEC points shown in the table. The worst results... 

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