INFRARED CHEMILUMINESCENCE STUDIES OF H+BRCN AND H ABSTRACTION BY CN REACTIONS - IMPORTANCE OF THE HNC CHANNEL

The H+BrCN reaction and the H abstraction reactions from HI, H2S, PH3, SiH4, CH3OCH3, c-C5H10 and C(CH3)4 by CN were studied by infrared chemiluminescence in a fast flow reactor. From the dependence of the HCN and HNC emission intensities on temperature, activation energies of 5.2 +/- 0.4 and 7.5 +/- 0.8 kcal mol-1 were assigned for the HCN and HNC channels from the H+BrCN reaction. The anharmonicity constant, X3,3 for HNC, was determined to be 66 cm-1. All reactions yielded HCN with an inverted vibrational distribution in nu3 along with nu2 excitation and [f(upsilon)] = 0.4-0.5. The abstraction reactions from PH3 and HI produced HNC (upsilon3, greater-than-or-equal-to 1) with HNC/HCN ratios of greater-than-or-equal-to 0.02 and greater-than-or-equal-to 0.43, respectively.