Infrared photofragmentation of 'hot' and 'cold' nitric oxide cluster ions

摘要

A line-tunable CO laser has been used to record infrared absorption profiles for (NO)_n~+ and (NO)_n~+. Ar clusters for n in the range 2-19 and at wavelengths between 1600 and 1900 cm~(-1). The presence of an argon atom is shown to have the effect of reducing the internal energy content of the ions, and for the case of (NO)_2~+. Ar is the only circumstance under which infrared absorption can be detected for the dimer ion. The trimer ion, (NO)_3~+, is found to have a very strong absorption feature at approx 1700 cm~(-1), which remains both static and comparatively narrow in subsequent cluster ions containing up to 19 nitric oxide molecules. It is concluded that (NO)_3~+ forms a stable core in larger clusters and that there is very little additional charge delocalization.