Abstract: Configurations and properties of unsaturatedcarbenoid H2C=CLiF have been obtained by using DFT method at B3LYP/6311G level.The results show that H2C=CLiF has two equilibrium configurations 1 and 2(Fig.3).The transition state of isomerization of 1 to 2 has also been obtained (Fig.3).Thermodynamic and kinetic properties of isomerization of 1 to 2 have been calculated according to statistical mechanics and transition state theory.Thermodynamic properties show that 1 is more stable than 2 in the temperature range of 100～1000 K,and the kinetic properties show that the rate of transformation from 2 to 1 is very fast.So 1 is the only “stable equilibrium species” existed in unsaturatedcarbenoid H2C=CLiF.Vibrational frequencies and infrared intensities of stable equilibrium 1 at B3LYP/6311G level have been given.

Key words: Unsaturatedcarbenoid H₂C=CLiF, DFT(density functional theory), B3LYP/6-311G, Thermodynamic property, Kinetic property