Ab iniotio and density functional theory study of diazene isomerization

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:447603

Jursic, B S ^[1]

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1. Univ. of New Orleans, LA (United States)

The HF, MP2, QCISD(T), GI, G2, and G2MP2 A initio and the twenty-two Density Functional Theory (DFT) methods were used to perform the computational study of sin- and cis-diazene transformation into trans-diazene. In all of the calculations, the Gaussian type 6-311 + G(2d,2p) basis set was used. The DFT computed geometries and energies are compared with the ab initio results. In addition, the validity of several DFT methods for studying these and similar molecular systems is evaluated. The energies computed with the G2MP2 ab initio calculations is believed to be the most accurate. Thus the activation barrier for the cis-trans isomerization is 44.6 kcal/mol and the enthalpy of reaction is 5.0 kcal/mol. The reaction barrier for the sin-trans isomerization is 45.2 kcal/mol and the enthalpy of reaction is 24.2 kcal/mol. The closest computed values to the G2MP2 energies are obtained using the BPW91 and BLYP, which are nonlocal methods, followed by the B3PW9I and B3LYP hybrid DFT methods. In the best case, the energies differ by less than 3 kcal/mol.

• OSTI ID: 447603
• Report Number(s): CONF-960343--
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ACTIVATION ENERGY
CALCULATION METHODS
DIAZOTIZATION
ELECTRON DENSITY
FUNCTIONALS