Hydrogen bonding, semiempirical

To verify the influence of the surrounding hydrogen bonds, semiempirical model calculations (PM3) were performed [85]. The donor and acceptor groups around the... 

AMI Cambridge Structural Database Carbohydrate Force Fields Conformational Analysis 1 Conformational Analysis 2 Conformational Analysis 3 Continuum Solvation Crystal Structure Calculations 1 Crystal Structure Calculations 2 Cyclodextrins Force Fields MM3 Hydrogen Bonding 1 Hydrogen Bonding 2 Hydrogen Bonds Semiempirical Methods Hyperconjugation MNDO Natural Bond Orbital Methods PM3 Solvation Carbohydrates. 

Hydrogen Bonding 1 Hydrogen Bonds Semiempirical Methods Water Clusters. 

AMI Divide and Conquer for Semiempirical MO Methods Green s Function Ionization Potentials in Semiempirical MO Theory Hydrogen Bonds Semiempirical Methods Localized MO SCF Methods MNDO/d Parameterization of Semiempirical MO Methods PM3 Polymers Semiempirical Calculations Population Analyses for Semiempirical Methods Semiempirical Vibrational Frequencies (Including Scaling). 

In order to include other interactions such as dipolar or hydrogen bonding, many semiempirical approaches have been tried [196, 197, 200], including adding terms to Eq. X-45 [198, 201] or modifying the definition of [202, 199]. Perhaps the most well-known of these approaches comes from Fowkes [203, 204] suggestion that the interactions across a water-hydrocarbon interface are dominated by dispersion forces such that Eq. X-45 could be modified as... 

Another, more semiempirical, method is to assume that the only effect of the catalyst is to change the binding to the surface entropy and solvation effects are taken to be the same as for the solvated spices. This assumes that the hydrogen bonds to, e.g., OH are the same as the hydrogen bonding to OH [Roques and Anderson, 2004]. We... 

However, another study concluded that the changes of the hydrogen-bond stability may be important in biological processes. For these, the influence of local electric fields created by Li+, Na+, and Mg2+ ions on the properties and reactivity of hydrogen bonds in HF and HC1 dimer has been carried out by means of ab initio self-consistent field (SCF) method [33]. A few years later, the effect of intensity and vector direction of the external electric field on activation barriers of unimole-cular reactions were studied using the semiempirical MINDO/3 method [34]. However, both semiempirical and ab initio calculations were performed to study the multiplicity change for carbene-like systems in external electric fields of different configurations (carbene and silylene) and the factor that determines the multiplicity and hence the reactivity of carbene-like structures is the nonuniformity of the field [35]. 

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