In this letter, we report the singlet ground state structure of the full carotenoid peridinin by means of variational Monte Carlo (VMC) calculations. The VMC relaxed geometry has an average bond length alternation of 0.1165(10) Å, larger than the values obtained by DFT (PBE, B3LYP, and CAM-B3LYP) and shorter than that calculated at the Hartree-Fock (HF) level. TDDFT and EOM-CCSD calculations on...

In this paper, the structural properties of the B30N20 molecule have been investigated at B3LYP/6-31G (d) level of theory. The optimized structure and electronic properties calculations for the studiedmolecule have been performed using Gaussian 03 program. A mathematical equation of third degreewas exploited for the correlation and exchange energy with the number of primitives. The NaturalBondi...

The mechanism of the enantioselective deprotonation of cyclohexene oxide with isopinocampheyl-based chiral lithium amide was studied by quantum chemical calculations. The transition states of eight molecules were fully optimized at the ab initio HF/3-21G and density functional B3LYP/3-21G levels with Gaussian 98. The activation energies were calculated at the B3LYP/6-31+G(3df,2p)//B3LYP/3-21G l...

Density functional calculations were used to explore the complexation of 3-alkyl-4-phenylacetylamino-4,5-dihydro-1h-1,2,4-triazol-5-one (ADPHT) derivatives by first-row transition metal cations. Neutral ADPHT ligand and mono deprotonated ligands have been used. Geometry optimizations have been performed in gas-phase and solution-phase (water, benzene, and N,N-dimethylformamide (DMF)) with B3LYP...

the structural stabilities, geometry and electronic properties of c24 and some its heterofullerenederivatives are compared at the b3lyp/6-311-efg**//b3lyp/6-31+g* level of theory. vibrationalfrequency calculations show that all the systems are true minima. the calculated binding energies ofheterofullerenes show c24 as the, most stable fullerenes by 9.03ev/atom. while decreasing bindingenergy in...

structural and magnetic properties of purine and pyrimidine nucleotides (cmp, ump, dtmp, amp, gmp, imp) were studied at different levels of ab initio molecular orbital theory. these calculations were performed at the hartree-fock level and density functional b3lyp methods. geometries were fully optimized by following cs symmetry restrictions. the standard 6-31g** basis set which includes polari...

The potential of various organic species to catalyze epoxidation of ethene by hydrogen peroxide is explored with B3LYP/6-31G* DFT calculations.

In the present work, the regioselectivity for a series of Diels–Alder reactions (4 reactions) has beenstudied using hardness, electrophilicity and polarizability of products.Furthermore,thermodynamicand kinetic calculations have been done. In all results predicted pararegioisomer is more favorableregioisomerinthese investigated reactions.All calculations have been done at the DFT-B3LYP/6-31G(d)...

First-principles anharmonic calculations are carried out for the CH stretching vibrations of isolated toluene and compared with the experimental infrared spectra of isotopologues of toluene in a Ne matrix at 3 K and of liquid toluene at room temperature. The calculations use the vibrational self-consistent field method and the B3LYP potential surface. In general, good agreement is found between...