High temperature, high resolution infrared spectral measurements on the HNC–HCN equilibrium system

Spectral measurements have been made on HNC in equilibrium with HCN at temperatures ranging from 900 to 1250 K. From measurements of absorption intensity vs temperature it is determined that the ground state of HNC is 10.3±1.1 kcal/mol (43.1±4.6 kJ/mol) above the ground state of HCN. High resolution data are given on the following vibrational transitions for HNC near 3650 cm−1: 1000–0000, 1110–0110, 1200–0200, and 1220–0220. Measurements near 2780 cm−1 are also given for the 1000–0000 and 1110–0110 transitions for DNC. Aside from the low bending force constant, these measurements show nothing unusual about the bending potential function.