Ab initio calculation
of vibrational absorption and circular dichroism spectra using density functional force fields.
In this work we present ab initio calculation
of structural optimization and electronic properties using density functional theory while the time dependent and excited state properties (optical gap) of Si, Ge and Si/Ge nanocrystals based on time dependent density functional theory (TDDFT)  employing the hybrid nonlocal exchange-correlation functional of Becke and Lee, Yang and Parr (B3LYP) .
Frisch, "Ab Initio calculation
of vibrational absorption and circular dichroism spectra using density functional force fields," Journal of Physical Chemistry, vol.
Fan, "Visible-light photocatalytic activity of Ni-doped Ti[O.sub.2] from ab initio calculations
," Materials Chemistry and Physics, vol.
Based on ab initio calculations
, we predicted that only G would form a stable base pair with Oz 8-10].
We use the pair potential known as [[empty set].sub.07], which was developed by Hurly and Mehl (6) based on the best ab initio calculations
available in 2007.
This view is supported by the energetics of the different configurations- The semiempirical PM3 and ab initio calculations
also provide an estimate of the total energy of the four structural phases, which is the net result of electronic kinetic energies and the interactions between all electrons and atomic cores in the system.
Ab initio calculations
for 1 and 3 predict that twist-boat conformation is lower in free energy than the chair conformation, whereas chair (ax) form is found to be more stable for 2.
HF/3-21G* ab initio calculations
on methoxy-substituted bithiophenes.
The optimized geometries, conformational stabilities, infrared intensities, Raman Activities, depolarization ratios and vibrational wave number have been obtained from MP2/6-31G(d) ab initio calculations
. These quantities are compared to the correspondence experimental quantities when appropriate.
Ab Initio calculations
were performed al the CASPT2 level of theory (CAS(4,4)), using Dunning's augmented basis Sets (spdf for Ne and N, and spd for It).