The band of ND3 studied by laser-induced amplified spontaneous emission and transient gain spectroscopy
2004; Elsevier BV; Volume: 303; Issue: 3 Linguagem: Inglês
10.1016/j.chemphys.2004.06.019
ISSN1873-4421
AutoresYoshihiro Ogi, Koichi Tsukiyama∥,
Tópico(s)Photochemistry and Electron Transfer Studies
ResumoTwo nonlinear laser spectroscopic methods have been employed for interrogating the C̃′1A′1→Ã1A2′′ transition of ND3. The first method utilized laser-induced amplified spontaneous emission (LIASE) as the signal radiation. When single rovibronic levels in the C̃′1A′1 (2n,n=1–7) states of the ND3 molecules were populated through two-photon excitation from the X̃1A1 state by pulsed UV laser light, yellow LIASE was generated along the input laser axis. The qQ branches with J=K dominated both the C̃′←X̃200 excitation and C̃′→Ã211 LIASE spectra. LIASE was almost perfectly polarized parallel to the polarization plane of the incident UV radiation. The second method, transient gain spectroscopy (TGS), in which the stimulated emission induced by the injection of weak DUMP radiation is detected, was also applied to the C̃′→Ã211 band system. The amplification of DUMP laser intensities at the exit of the ND3 sample cell was successfully observed when the DUMP frequencies were resonant with the specific rovibronic lines in the C̃′→Ã band. The maximum gain was as large as 75. TGS spectra exhibited narrower line widths than the natural line widths estimated from the lifetimes of lower levels.
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