Emission and Absorption Spectra of NCO and NCS

The Photolysis of Isocyanic Acid Vapor

“…The observed values of N2:C0, and the very low yields of Hz, would appear to favor reaction [2] which would have led t o a product ratio C0:Nz:Hz of 2:l:l. I t will be seen later that the persistent low yield of hydrogen a t high pressures of HNCO (Fig. 3) Reaction [4] was suggested previously to be the fate of NCO radicals in the photolysis of methyl isocyanate (13).…”

“…Values of kz/k&'2 were obtained from the slopes of these plots, and if Eb = 0, a very rough estimate of Ez = 3.6 kcal/mole may be made. In a simple competition between reactions [j] and [2], the H2:CO ratio should have fallen t o zero a t high pressures of H S C O , but it is seen instead that the ratio reached a constant value, small but measurable, a t 37 and 100" C (Fig. 3).…”

“…The simple mechanism comprising reactions [I], [2], [3], and [4] predicts a ratio of N2:CO of 0.33, corresponding t o the upper horizontal line in Fig. 2.…”

“…[5 1 A simple kinetic treatment of a competition between reactions [5] and [2] yielded reasonably linear plots of Rz/R5112 against HNCO concentration for the data a t 0 and 37" C and low pressures of HNCO. Values of kz/k&'2 were obtained from the slopes of these plots, and if Eb = 0, a very rough estimate of Ez = 3.6 kcal/mole may be made.…”

Molecular Spectroscopy: Some Personal Reminiscences

“…Although the spectra were taken with very low resolution, the spectral region and the possible carrier were still of great interest because it might be possible to obtain high-resolution spectra in absorption using flash photolysis. Indeed, on my return, my colleagues and I did obtain absorption spectra of two of the radicals, NCO and NCS, which we published jointly with Style & Holland (34).…”