Kinetics of OCN super( -) formation from the HNCO + NH sub( 3) solid-state thermal reaction

Solid-state features in infrared astronomical spectra can provide useful information on interstellar ices within different astrophysical environments. Solid OCN... has an absorption feature at 4.62 mu m, which is observed in star formation regions only with a large source-to-source abundance variation. The authors aim to investigate the thermal formation mechanism of solid OCN... from HNCO on the basis of kinetic arguments. They experimentally studied the kinetics of the low-temperature OCN... formation from the purely thermal reaction between HNCO and NH3 in interstellar ice analogs using Fourier transform infrared spectroscopy. The kinetics can de divided into two-processes, a fast process corresponding to the chemical reaction, and a slow process that the authors interpret as the spatial orientation of the two reactants within the ice. The present experiment has the important implication that the HNCO + NH3 reaction can account for the observed abundances of solid OCN... and the HNCO non detection in young stellar objects. (ProQuest: ... denotes formulae/symbols omitted.)