PHASE-SHIFT STUDIES OF THE QUENCHING OF NH(C1-PI) AND NH(A3-PI) BY HYDROCARBONS

The cross-sections for quenching NH(c1II) and NH(A3II) by hydrocarbons were determined at room temperature by using a phase-shift method. The NH(c1II) was produced by the photolysis of HN3 using an amplitude-modulated Xe-resonance lamp. The apparent decay rate of the NH(c1II) was estimated from the difference in phase angle between the excitation light and the fluorescence of NH(c1II) at 325 nm. In the presence of Xe, the fluorescence of NH(A3II) at 336 nm was enhanced. The difference in the phase angle between the fluorescences at 325 and 336 nm was found to correlate with the decay rate of NH(A3II). From the decay rates obtained in the presence of hydrocarbons, the quenching cross-sections were determined. © 1986 The Chemical Society of Japan.