Fourier Transform Infrared Spectroscopy of Nitric Oxide during Exposure to Vacuum Ultraviolet Radiation

The FT-IR spectrum of chemically pure (C.P.) NO was obtained while the gas was being irradiated by radiation at 121.5 nm. A novel cell design allows the ultraviolet radiation and the infrared probe beam to be co-linear. The exposure time of the gas to the UV radiation ranged from 0 to 100 minutes. Spectra were collected at evenly spaced time intervals during irradiation by the UV radiation. The composition of the gas changed as a function of irradiation time. Experimental results were compared with the calculated change in the composition of the gas by solving a set of simultaneous differential equations based on a kinetic model, giving good agreement. It is shown that the cell may also be used as an actinometer, and may be used as a check on the applicability of some rate equations to reacting systems.