Infrared spectroscopy and photochemistry of NCCN+ and CNCN+ trapped in solid neon

When a Ne:NCCN sample is codeposited at 4.3 K with neon atoms that have been excited in a microwave discharge, the infrared and near infrared spectra of the resulting deposit include a prominent peak at 1799.5 cm-1, previously assigned to nu3 of NCCN+, and several new absorptions at higher frequencies which are contributed by combination bands of ground-state NCCN+. The exposure of the deposit to near infrared and red light results in the appearance of two new absorptions which are attributed to CNCN+. The reverse isomerization occurs when the sample is exposed to near ultraviolet radiation, but the two new absorptions are regenerated upon subsequent irradiation with near infrared and red light.