The enthalpy△H, free energy △G, equilibrium constant K, and reaction rate constant k (T) in Eyring transition state theory of cyclopropylsilylene C3H5SiH have also been calculated.

The reaction mechanism of 8-dimethyl-7-methoxy-5-ethenyl-nonanenitrile oxide cycloaddition has been studied with the molecular orbital AM1 method and transition state theory.

Based on the quantum chemical study of the SiH insertion reactions with H2O and H2S, the statistical thermodynamics and Eyring transition state theory with Wigner correction are employed to compute the thermodynamic functions, equilibrium constants, A factors and rate constants of the two reactions in the temperature range 200～2000 K.

The rate constant of the reaction calculated by using the improved canonical variational transition state theory(ICVT) was in agreement with that of the experimental value in the temperature range of 1300—2100K.

The rate constants of the reactions were evaluated by means of the classical transition state theory, the canonical variational transition state theory, and canonical variational transition state theory incorporating small-curvature tunneling correction in the temperature range of 200～2000 K.

The reaction mechanism of 7-methoxy-5-ethenyl-octanitrile oxide cycloadditions have been studied with the molecular orbital AM1 method and transition state theory. The result showed that the titled compound generates the two stereoisomers(P a and P s)via transition states TS a and TS s respectively. The stereoselectivity was determined by the ratio of the rate constants of two reactions.

The effects of m ( p nitrophenyl), m phenyl and m ( p methylphenyl) on the isomerization reaction of porphine are studied by using AM1 MO method and transition state theory.

The reaction mechanism of the enantioselectivity in oxazaborolidine catalyzed reductions of phenyl ethyl ketone has been studied by using AM1 method and transition state theory. The results show that the boron catalyzed reactions consist of two similar parallel reactions in which the reactants( R ) of the title compound and boron catalyst generate the enantiomers(P R and P S ) via intermediate compounds IC( R ) and IC( S ) and transition states TS R and TS S , respectively.

The reaction mechanism of the enantioselectivity in oxazaborolidine-catalyzed reductions of diphenyl diketohexane has been studied with the molecular orbital AM1 method and transition state theory. The results show that the boron-catalyzed reactions consist of two similar parallel reactions in which the reactants(R) of the title compound and boron-catalyst generate the enantiomers(P R and Ps)via intermendiate compounds IC(R) and IC(S) and transition states TS R and TS s respectively.

The rate constants were not in any disagreement with transition state theory.

The translational and rotational motions of molecules were described in terms of the transition state theory for nonideal reaction systems, which took into account the influence of neighboring molecules on the height of the activation barrier.

The migration of particles is described in terms of the transition state theory.

This dependence is difficult to explain in the framework of the accepted transition state theory.

A variant of the Kac-Zwanzig model is used to test the prediction of transition state theory (TST) and variational transition state theory (VTST).

The reaction path of the reaction CH3+OH→CH2+H2O is traced by Fukui's theory of intrinsic reaction coordinate using ab initio MO method with gradient technique. Furthermore, the dynamical properties along the reaction path and CVT (canonical variational theory) rate constants with correction of tunneling effect are investigated by reaction path Hamiltonian theory and variational transition state theory. The results show that the effects of CVT method are notable and the correction of tunneling effect is...

The reaction path of the reaction CH3+OH→CH2+H2O is traced by Fukui's theory of intrinsic reaction coordinate using ab initio MO method with gradient technique. Furthermore, the dynamical properties along the reaction path and CVT (canonical variational theory) rate constants with correction of tunneling effect are investigated by reaction path Hamiltonian theory and variational transition state theory. The results show that the effects of CVT method are notable and the correction of tunneling effect is also notable.

The intrinsic reaction coordinate(IRC)of the F shift rearrangement reaction are traced at the SCF MO/STO-3G level.Along the IRC,the vibrational frequencies of normal modes and the coupling constants(Bk,f,)between the IRC and other normal modes are calculated.According to conventional transition state theory,variational transition state theory and tunneling corrections,the reaction rate constants of this rearrangement reaction are obtained. In addition,the vibrational state distributions of...

The intrinsic reaction coordinate(IRC)of the F shift rearrangement reaction are traced at the SCF MO/STO-3G level.Along the IRC,the vibrational frequencies of normal modes and the coupling constants(Bk,f,)between the IRC and other normal modes are calculated.According to conventional transition state theory,variational transition state theory and tunneling corrections,the reaction rate constants of this rearrangement reaction are obtained. In addition,the vibrational state distributions of this reaction are investigated under different energies by using the semiclassical perturbation(SCP)approximation and the infinite order sudden(IOS)approximation.The calculated results show that when the reaction coordinate S>0 the magnitude of coupling constants(Bk,f,)will notably affected the distribution probabilities of vibrational states of the product.

The regioselectivity of intramolecular N-4-hexenyl nitrone cycloaddition has been investigated by AMI MO method and transition state theory. Two isomeric products and corresponding transition states were located by energy gradient technique. The ratio of the rate constants of these two parallel reaction (kb/ka) is calculated to be 25.46, which is in good consistence with experiments. In comparison of this ratio with that of N-4-pentenyl nitrone cycloaddition, which is 1.21, it is realized that...

The regioselectivity of intramolecular N-4-hexenyl nitrone cycloaddition has been investigated by AMI MO method and transition state theory. Two isomeric products and corresponding transition states were located by energy gradient technique. The ratio of the rate constants of these two parallel reaction (kb/ka) is calculated to be 25.46, which is in good consistence with experiments. In comparison of this ratio with that of N-4-pentenyl nitrone cycloaddition, which is 1.21, it is realized that N-5-methyl substituent changes the regioselectivity notably. The main reason is that the electronic effect of N-5-methyl makes the activation enthalpy of reaction b reduced and the configuration change by introducing an N-5-methyl group makes the activation entropy of reaction b increased.