Deuterium kinetic isotope effects and their temperature dependence in the gas-phase SN2 reactions X(super -) + CH3Y gives CH3X + Y(super -)(X, Y = Cl, Br, I)

The calculated kinetic isotopic effect (KIE) and their temperature dependence for gas-phase S(sub N)2 reactions X(super -) + CH3Y gives CH3X + Y(super -)(X, Y = Cl, Br, I) are consistent with the experimentally established data. Small alterations of the transition state theory from conventional transition state occurs. The KIE is susceptible to vibrational frequencies. Anharmonicity have substantial effect on the experimental results. Rate constants exhibit negative correlation below 500 K.