Abstract: The thermochemical properties of reaction N++H2→NH++H have been computed under Titan′s atmosphere conditions. It is observed that this reaction is an endothermic reaction and cannot proceed forward spontaneously under low temperature. The rate for this reaction at 300 K has been calculated as k=4.16×10−10 cm3•mol−1•s−1. The reaction barrier is 109.847 kJ•mol−1 at 298.15 K, which is probably too high to allow this reaction to occur in the atmosphere of Titan. The kinetic properties of the reaction are calculated at a pressure of 90 Pa and a temperature ranging from 1 to 5000 K. It is found that this reaction has very low reaction rate under low temperature in Titan′s atmosphere and that the rate decreases drastically with decreasing temperature. This result should be applicable to interstellar place of the low temperature values. The results are compared with those obtained from experiments.

Key words: Titan, Thermodynamic, Activation free energy, Reaction rate