Emission induced by interaction between nitrogen molecules and electronic excitations of α-quartz single crystal

Abstract

The spectral and kinetic characteristics of emission in the region of 300–380 nm caused by photoexcitation of α-quartz single crystal placed into gases of N2 molecules, He atoms and atmospheric air are studied. It is found that the interaction between electronic excitations (EE) created in α-quartz by the two-photon absorption at 205 nm with surrounding N2 molecules leads to emission of a complex “α-quartz surface – N2 molecule”. This fact is proved, particularly, by the growth in the radiant energy of studied emission correlated with the increase in the N2 gas pressure in the region of 0.1–200 Torr. Simultaneously, the spectral energy distribution of the emission as a function of wavelength differs from that for a free N2 molecule. This result shows that the electronic-vibrational states of N2 molecules are significantly distorted due to interaction with α-quartz surface. The results are explained by excitation of the intercombinational X1Σg+→ C3Πu transition of N2 molecules induced by the energy transfer from the EEs in α-quartz and subsequent short-term chemical bond formation between the excited N2 molecules and the α-quartz surface.