Interdependence of Fluence and Pressure in the Laser-Induced Isomerization of Methyl Isocyanide

Article abstract of DOI:10.1021/j100247a016

The infrared laser-induced isomerization of methyl isocyanide has previously been shown to exhibit a marked pressure dependence; large-scale isomerization occurs when threshold conditions have been exceeded.In this work the wavelength and fluence dependence of the pressure threshold have been investigated.It has been determined that threshold conditions reflect a balance between the average level of excitation and the sample pressure.The multiphoton spectrum and the treshold as a function of wavelength have been determined and both reflect the structure of the linear absorption spectrum, indicating that the effective anharmonicity is small.In addition, the earlier conclusion that the threshold is not due to a laser-triggered, thermal explosion is corroborated.