energy using the small 6-31G�d) basis set
ثبت نشده
چکیده
Gaussian-3 ground-state total electronic energies have been approximated using single point 6-31G(d) basis set Harteee±Fock self-consistent-®eld (HF-SCF) total energies and partial charges based on our earlier rapid estimation of correlation energy from partial charges method. Sixty-®ve closed-shell neutral molecules (composed of H, C, N, O, and F atoms) of the G2/97 thermochemistry database were selected for the present study. The main feature in this work is that the basis set error has been treated by the least squares ®t of rapid estimation of basis set error and correlation energy from partial charges (REBECEP) atomic parameters. With these parameters a rather accurate closed-shell ground-state electronic total energy can be obtained from a small basis set HF-SCF calculation in the vicinity of stationary points. The average absolute deviation of the best REBECEP enthalpies of formation from the experimental enthalpies of formation is 1.39 kcal/mol for the test set of 65 enthalpies of neutral molecules.
منابع مشابه
Ab initio study of the second virial coefficient protein — protein on the basis of intermolecular potential energy surface
Intermolecular potential energy surface (IPS) for protein — protein has been examined using RHF, DFT-B3LYPand MP2 levels of theory with 6-31G, 6-31G* basis sets. A number of basis sets were used in order to evaluatethe basis set effects, at all three levels of theory, basis sets has significant effects on the calculated potentialenergy curves (including position, depth and width of the potentia...
متن کاملRelaxed Energetic Maps of j-Carrabiose: A DFT Study
The B3LYP density function was used with the 6-31G(d) basis set to perform relaxed energetic contour maps of the charged form of j-carrabiose in the gas phase and for the neutral form first in the gas phase and then by simulating the presence of water as solvent using the Onsager model. Only one starting conformation has been considered to perform all the calculations. Rigid energetic maps have...
متن کاملStudy of Photoisomerization in Cis-Retinal as a Natural Photo Switch in Vision Using Density Functional Theory
In the present study, theoretical chemical reactivates Photo isomerization in Cis-Retinal as a Natural Photo switch in Vision. DFT hybrid functional, B3LYP and, post-HF method, were the theoretical methods applied utilizing G09 software. 6-31G+ (d,p) basis set employed for structural optimizations, and single point computations performed using B3LYP/6-31G+(d,p). The isomers cis molecule retinal...
متن کاملC – H ̄ O H - bonded complexes : How does basis set superposition error change their potential - energy surfaces ?
Geometries, vibrational frequencies, and interaction energies of the CNH ̄O3 and HCCH ̄O3 complexes are calculated in a counterpoise-corrected ~CP-corrected! potential-energy surface ~PES! that corrects for the basis set superposition error ~BSSE!. Ab initio calculations are performed at the Hartree–Fock ~HF! and second-order Mo”ller–Plesset ~MP2! levels, using the 6-31G(d ,p) and D9511(d ,p) bas...
متن کاملStudy of Photoisomerization in Cis-Retinal as a Natural Photo Switch in Vision Using Density Functional Theory
In the present study, theoretical chemical reactivates Photo isomerization in Cis-Retinal as a Natural Photo switch in Vision. DFT hybrid functional, B3LYP and, post-HF method, were the theoretical methods applied utilizing G09 software. 6-31G+ (d,p) basis set employed for structural optimizations, and single point computations performed using B3LYP/6-31G+(d,p). The isomers cis molecule retinal...
متن کامل