The hybrid density functional theory (B3LYP) and ab initio molecular orbital (HF) based methods and Natural Bond Orbital (NBO) interpretation were used to analyze the conformational behaviors of 2,5,5-trimethyl-1,3,2-dioxaphosphinane 2-selenide (compound 1), 2,5,5-trimethyl-1,3,2-dithiaphosphinane 2-selenide (compound 2) and 2,5,5-trimethyl-1,3,2-diselena phosp...

Conformational analysis of 2,6-dideoxy-2-halo-alpha-L-hexopyranoses (compounds 1-11) has been performed by molecular mechanics and molecular orbital calculations including solvation effects. The numerical results obtained and those obtained from the electrostatic potential calculation have been used together to interpret theoretically the influence of the introduction of the halogen atom at the...

Z. Naturforsch. 38 b, 1635-1642 (1983); received June 7, 1983 Walk Rearrangement, Cyclopentadienylphosphanes, Molecular-Orbital Study The walk rearrangement of cyclopentadienylphosphanes and related compounds is analyzed on the basis of a quantum chemical study. Although according to orbital symmetry considerations the reaction takes place with retention of configuration (at the migrating atom)...

In the strong field molecular tunnelling ionization theory (Tong X M 2002 Phys. Rev. A 66 033402), the ionization rate depends on structure parameters of molecules which can be extracted from molecular wavefunctions in the asymptotic region. By using molecular orbitals obtained from standard quantum chemistry packages, we extract these parameters for several selected nonlinear polyatomic molecu...

A simple theory of hydrogenic screened orbitals was studied theoretically at least as early as 1981 and empirically since the 1930s. Its present form is appropriate for undergraduate students. This presentation begins with the Rydberg atom, which has been known to be a reductive case for the electron orbital since at least 1928. The existence of such a limiting case has been denied in the philo...

We discuss the theory of electron-molecule excitation processes of importance in fusion plasmas. We consider elastic scattering, rotational, vibrational, and electronic excitation in turn and also dissociative attachment and impact dissociation.

The analysis of three pulse echo peak shift (3PEPS) data for LHI of Rhodobacter sphaeroides is discussed in comparison with that of the B820 subunit of Rhodospirillum rubrum. We report also ab initio molecular orbital (CIS/6-3IG*) calculations of electronic couplings for supermolecule subunits of the light harvesting 2 complex (LH2) of Rhodopseudomonas acidophila.

Ž . We investigate the use of the reaction-class approach within the integrated molecular q molecular orbital IMOMO methodology for improving energetic information of chemical reactions. We have tested this approach using two classes of hydrogen abstraction reactions. One is abstraction from saturated hydrocarbons and the other from unsaturated hydrocarbons. For saturated hydrocarbon systems, t...