caa a22 4500 463238850 CHVBK 20180405153306.0 cr unu---uuuuu 170326e20070101xx s 000 0 eng 10.1007/s10947-007-0002-3 doi (NATIONALLICENCE)springer-10.1007/s10947-007-0002-3 Relaxation of STO-3G and 6-31G* basis set functions in the series of LiF isoelectronic molecules of second row elements [Elektronische Daten] [A. Ermakov, V. Belousov] The relaxation effect of functions of STO-3G and 6-31G* basis sets (BS) on their balance is considered in the series of LiF, BeO, BN, and C2 isoelectronic molecules. The values of parameters (exponential factors of basis functions, orbital exponents of Gaussian primitives, and contraction coefficients for the basis functions in molecules are found by the energy minimum criterion from unrestricted Hartree-Fock (UHF) calculations with a direct optimization of parameters: the simplex and Rosenbrock methods. Several optimization schemes differing in the number of parameters varied are performed. An important, from the practical viewpoint, relation between parameters of the basis functions of the sets in question is found through the mean values of Gaussian exponents. The relaxation effect on the variation of the total energy and relative errors in the calculations of interatomic distances, normal vibration frequencies, dissociation energies, and other properties of molecules are examined. The variation of the total energy upon the relaxation of STO-3G and 6-31G* basis functions (RBF) can achieve 1100 kJ/mole and 80 kJ/mole, respectively, and should be taken into account when evaluating energy characteristics, especially for the systems with high polar chemical bonds. The relaxation of STO-3G BS improves the description of molecular properties almost in all cases considered, whereas the relaxation of 6-31G* BS slightly affects its balance. Springer Science+Business Media, Inc., 2007 quantum chemistry nationallicence basis set nationallicence relaxation nationallicence isoelectronic molecules nationallicence LiF nationallicence Ermakov A. Novomoskovsk Institute of Mendeleev Chemical Technology University of Russia, Russia aut Belousov V. Novomoskovsk Institute of Mendeleev Chemical Technology University of Russia, Russia aut Journal of Structural Chemistry Kluwer Academic Publishers-Consultants Bureau 48/1(2007-01-01), 6-15 0022-4766 48:1<6 2007 48 10947 https://doi.org/10.1007/s10947-007-0002-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10947-007-0002-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ermakov A. Novomoskovsk Institute of Mendeleev Chemical Technology University of Russia, Russia aut NATIONALLICENCE 700 1- Belousov V. Novomoskovsk Institute of Mendeleev Chemical Technology University of Russia, Russia aut NATIONALLICENCE 773 0- Journal of Structural Chemistry Kluwer Academic Publishers-Consultants Bureau 48/1(2007-01-01), 6-15 0022-4766 48:1<6 2007 48 10947 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer