MULTIPHOTON INDUCED ATOMIC NITROGEN-PRODUCTION IN A LOW-TEMPERATURE NITROGEN CRYSTAL

The emission from the 2D excited state of nitrogen atoms was observed when a low-temperature nitrogen crystal was irradiated by a focused ex cimer laser light at 248 nm. The emission intensity was found to incre ase linearly with the laser irradiation time. The increase rate of the emission was dependent on about the third power of the excitation las er intensity. It is concluded that nitrogen atoms and nitrogen molecul es in A 3SIGMA(u)+ state are produced through multi-photon processes. Nitrogen atoms accumulate and are excited repeatedly by energy transfe r from the excited nitrogen molecules.