Although mainly the DFT B3LYP
method at the 6-311+[G.
Chemical structures were optimized at the B3LYP
level using a 6-31G(d,p) basis set in the gas phase.
The widely employed hybrid method denoted as B3LYP
and, which includes a mixture of HF and DFT exchange terms and the gradient-corrected correlation functional of Lee et al.
All calculation used a 6-311G++(2d,2p) basis set and the B3LYP
level of density functional theory.
3] using HF, B3LYP
, and MP2 calculations with basis sets up to 6-31G*.
Moreover, the geometries of these compounds are fully optimized at DFT using B3LYP
hybrid functional method, with the 3-21G* and the 6-31G* basis sets, as implemented in Gaussian 03 program (30).
Optimizations were performed using B3LYP
density functional theory with a 6-31G(d) basis set, while final electronic energies were calculated using the 6-311+G(d) basis set.
The ground state geometries were optimized at the MP2, B3LYP
, and HF levels using 6-311++G(d,p) basis set.
methods provide excellent low-cost performance, as demonstrated in previous works reported in the literature (6), (7), (39), (45), (50-52).
Full geometry optimizations were performed with B3LYP
functional using the Dunning-Huzinaga valence double-zeta (D95V)  basis with a single set of polarization functions for carbon, hydrogen, oxygen, and nitrogen.
basis set were added to 3-21+G basis) and density functional calculations with the B3LYP
hybrid functional [30-33] and 6-31+[G.
Another approach would be to use a semiempirical hybrid functional like B3LYP
(17), (18) which is seen to work well in solid-state calculations for modeling the band gap (19), but density functional theory (DFT) is notorious for underestimating the band gap sometimes by a factor 2 or more (16), particularly for molecular systems, although DFT is excellent for estimating total energies in systems similar to PMVC (20).