Application of factorial design for the ab initio study of cis- and trans-1,2 dihaloethylene stabilities

Abstract

A técnica quimiométrica Planejamento Fatorial de Dois Níveis foi usada para avaliar os efeitos principais e de interação de modificações da função de onda no cálculo da diferença de energia (∆E) entre os isômeros cis e trans 1,2-dihaloetilenos, C 2 H 2 X 2 (X=F e Cl). O perfil fatorial é bastante diferente para esses dois sistemas. Os maiores efeitos no conjunto de base para a descrição do cis-1,2-difluoroetileno como o isômero mais estável são funções de polarização e funções difusas. Em contraste, correlação eletrônica, a nível MP2, e a inclusão de funções de polarização no conjunto de base são os maiores efeitos descrevendo o cis-1,2-dicloroetileno como o isômero mais estável. Em ambos os sistemas, os efeitos de interação são menores que os efeitos principais.The chemometric technique Two Level Factorial Design was used to evaluate the principal and interaction effects of wave function modifications on calculated energy differences (∆E) between the cis and trans isomers of 1,2-dihaloethylenes, C 2 H 2 X 2 (X=F and Cl). The factorial profile of ∆E is quite different for these systems. The addition of polarization and diffuse functions to the basis set have the largest effects in describing cis 1,2-difluoroethylene as the most stable isomer. In contrast electronic correlation, at the MP2 level, and the inclusion of polarization functions in the basis set have the largest effects in describing the cis form as the most stable one in the 1,2-dichloroethylenes. In both systems the interaction effects are smaller than the principal effects.

Geometric and Energetic Data from Ab Initio Calculations of Haloethene, Haloimine, Halomethylphosphine, Haloiminophosphine, Halodiazene, Halodiphosphene and Halocyclopropane

“…The total number of structures are summarized in Table 8. The dataset described in this paper is the most comprehensive compared to other previously published results on these compounds [3][4][5][6]. * If α is H there is no R/S and the number of total isomers must be calculated separately for this case.…”

Principal component analysis of molecular geometries of Cis- and trans-C2H2X2 with X = F or Cl

“…The Hartree-Fock (HF) 29 and Möller-Plesset of second order (MP2) 30 calculations were carried out using a 2 4 factorial design, where two levels of four factors were investigated: (i) the use of basis sets 6-31G or 6-311G; (ii) the presence or absence of diffuse functions; (iii) the presence or absence of polarization functions; (iv) the use, or not, of perturbative Möller-Plesset corrections of second order (MP2) to HF calculations. 16 The MP2 calculations were performed using the frozen-core electron correlation approach. The others were performed using coupled-cluster calculations with double excitations (CCD) and single and double excitations (CCSD) augmented by a perturbational correction for connected triple excitations [CCSD(T)].…”

“…15 Theoretical results have shown that a correct interpretation of this effect depends on the precision of the geometric parameters obtained from molecular orbital calculations. 16 However, calculated geometries can be strongly dependent on the calculation level (HF, MP2, CCD or [CCSD(T)]) and basis sets used whereas experimental [17][18][19][20][21][22] geometries may depend on the experimental technique employed (e.g. gas electron diffraction (GED) or microwave (MW) spectroscopy).…”

A theoretical study of the hydrogen bonding between the vic-, cis- and trans-C2H2F2 isomers and hydrogen fluoride

“…The vic-, cis-and trans-C 2 H 2 F 2 isomers have been the goal of several theoretical studies [8][9][10][11], in particular because these species contain the same kind and number of chemical bonds. Thus, it is expected that the major difference in their structural, electrical and vibrational properties can be attributed to the different 0022-2860/$ -see front matter Ó 2008 Elsevier B.V. All rights reserved.…”