Effective Hamiltonian hydrogen bonds

Figure C3.2.18.(a) Model a-helix, (b) hydrogen bonding contacts in tire helix, and (c) schematic representation of tire effective Hamiltonian interactions between atoms in tire protein backbone. From [23].

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... 

The autocorrelation function of the hydrogen bond within the effective Hamiltonian expression of the standard approach takes the form... 

Other semiempirical Hamiltonians have also been used within the BKO model. A Complete Neglect of Differential Overlap (CNDO/2) ° study of the effect of solvation on hydrogen bonds has appeared. o The Intermediate Neglect of Differential Overlap (INDO) °2 formalism has also been employed for this purpose.2011 Finally, the INDO/S model,which is specifically parameterized to reproduce excited state spectroscopic data, has been used within the SCRF model to explain solvation effects on electronic spectra.222,310-312 jhis last approach is a bit less intuitively straightforward, insofar as the INDO/S parameters themselves include solvation by virtue of being fit to many solution ultraviolet/visible spectroscopic data.29J... 

Here X = (x,y, z) Hp and Hq are the total Hamiltonians of the hydrogen bond and the lattice, respectively (it is supposed that the OHO bond is decoupled from the lattice system) m is the hydrogen mass q and M are the coordinate in the lattice system and the effective mass of the lattice s atom, respectively. H pq is an interaction Hamiltonian describing the interaction between the hydrogen and the lattice x is the coordinate of the hydrogen along the hydrogen bond y is a constant. 

In the case of hydrocarbons, the calculation still comprises five parameters, namely two Coulomb integrals ac and h, two bonds, resonance integrals /Sec and /Sqh and one resonance integral for two orbitals centered on the same carbon Ice- As usual, the interaction terms between non-bonded atoms are neglected. The parameters a and /3 are the matrix elements of a non-specified effective Hamiltonian with respect to the sp3 or sp2 hybrid orbitals of carbon and the Is orbitals of hydrogens. For the a bonds of conjugated hydrocarbons 4S>, the following set of values has been used... 

Two neighbor molecules interact via van der Waals and hydrogen bonding of energies given, respectively, by parameters e and e + y. The model is described by the following effective Hamiltonian, in the grand-canonical ensemble ... 

ACES II Anharmonic Molecular Force Fields Bench-mark Studies on Small Molecules Complete Active Space Self-consistent Field (CASSCF) Second-order Perturbation Theory (CASPT2) Configuration Interaction Core-Valence Correlation Effects Coupled-cluster Theory Density Functional Theory (DFT), Hartree-Fock (HF), and the Self-consistent Field G2 Theory Heats of Formation Hybrid Methods Hydrogen Bonding 1 M0ller-Plesset Perturbation Theory NMR Data Correlation with Chemical Structure Photochemistry Proton Affinities r 2 Dependent Wave-functions Rates of Chemical Reactions Reaction Path Following Reaction Path Hamiltonian and its Use for Investigating Reaction Mechanisms Spectroscopy Computational... 

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