Evaluation of density functionals and basis sets for carbohydrates

Correlated ab initio wave function calculations using MP2/aug-cc-pVTZ model chemistry have been performed for three test sets of gas phase saccharide conformations to provide reference values for their relative energies. The test sets consist of 15 conformers of Rand β-D-allopyranose, 15 of 3,6-anhy...

Descripción completa

Guardado en:
Detalles Bibliográficos
Publicado: 2009
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15499618_v5_n4_p679_Csonka
http://hdl.handle.net/20.500.12110/paper_15499618_v5_n4_p679_Csonka
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_15499618_v5_n4_p679_Csonka
record_format dspace
spelling paper:paper_15499618_v5_n4_p679_Csonka2023-06-08T16:21:28Z Evaluation of density functionals and basis sets for carbohydrates Correlated ab initio wave function calculations using MP2/aug-cc-pVTZ model chemistry have been performed for three test sets of gas phase saccharide conformations to provide reference values for their relative energies. The test sets consist of 15 conformers of Rand β-D-allopyranose, 15 of 3,6-anhydro-4-O-methyl-D-galactitol, and four of β-D-glucopyranose. For each set, conformational energies varied by about 7 kcal/mol. Results obtained with the Hartree-Fock method, with pure density functional approximations (DFAs) like LSDA, PBEsol, PBE, and TPSS and with hybrid DFAs like B3PW91, B3LYP, PBEh, and M05-2X, were then compared to the reference and local MP2 relative energies. Basis sets included 6-31G*, 6-31G**, 6-31+G*, 6-31+G**, 6-311+G**, 6-311++G**, cc-pVTZ(-f), cc-pVTZ, and augcc-pVTZ(-f). The smallest basis set that gives good DFA relative energies is 6-31+G**, and more converged results can be obtained with 6-311+G**. The optimized geometries obtained from a smaller basis set, 6-31+G*, were useful for subsequent single point energy calculations with larger basis sets. The best agreement with MP2 was shown by M05-2X, but only when using a dense DFT grid. The popular B3LYP functional is not the best for saccharide conformational studies. The B3PW91 functional gives systematically better results, but other hybrid functionals like PBEh or TPSSh are even better. Overall, the nonempirical PBE GGA and TPSS meta-GGA functionals also performed better than B3LYP. © 2009 American Chemical Society. 2009 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15499618_v5_n4_p679_Csonka http://hdl.handle.net/20.500.12110/paper_15499618_v5_n4_p679_Csonka
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description Correlated ab initio wave function calculations using MP2/aug-cc-pVTZ model chemistry have been performed for three test sets of gas phase saccharide conformations to provide reference values for their relative energies. The test sets consist of 15 conformers of Rand β-D-allopyranose, 15 of 3,6-anhydro-4-O-methyl-D-galactitol, and four of β-D-glucopyranose. For each set, conformational energies varied by about 7 kcal/mol. Results obtained with the Hartree-Fock method, with pure density functional approximations (DFAs) like LSDA, PBEsol, PBE, and TPSS and with hybrid DFAs like B3PW91, B3LYP, PBEh, and M05-2X, were then compared to the reference and local MP2 relative energies. Basis sets included 6-31G*, 6-31G**, 6-31+G*, 6-31+G**, 6-311+G**, 6-311++G**, cc-pVTZ(-f), cc-pVTZ, and augcc-pVTZ(-f). The smallest basis set that gives good DFA relative energies is 6-31+G**, and more converged results can be obtained with 6-311+G**. The optimized geometries obtained from a smaller basis set, 6-31+G*, were useful for subsequent single point energy calculations with larger basis sets. The best agreement with MP2 was shown by M05-2X, but only when using a dense DFT grid. The popular B3LYP functional is not the best for saccharide conformational studies. The B3PW91 functional gives systematically better results, but other hybrid functionals like PBEh or TPSSh are even better. Overall, the nonempirical PBE GGA and TPSS meta-GGA functionals also performed better than B3LYP. © 2009 American Chemical Society.
title Evaluation of density functionals and basis sets for carbohydrates
spellingShingle Evaluation of density functionals and basis sets for carbohydrates
title_short Evaluation of density functionals and basis sets for carbohydrates
title_full Evaluation of density functionals and basis sets for carbohydrates
title_fullStr Evaluation of density functionals and basis sets for carbohydrates
title_full_unstemmed Evaluation of density functionals and basis sets for carbohydrates
title_sort evaluation of density functionals and basis sets for carbohydrates
publishDate 2009
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15499618_v5_n4_p679_Csonka
http://hdl.handle.net/20.500.12110/paper_15499618_v5_n4_p679_Csonka
_version_ 1768543293276160000

Ejemplares similares