Observation of the 2ngr;2(l=2)larr;0 overtone band of H+3

摘要

The overtone band of 2ngr;2(l=2)larr;0 of H+3in the 2 mgr;m infrared region has been observed in absorption by using a difference frequency laser spectrometer. The LiIO3nonlinear optical system assembled by Bawendi and the bidirectional multiple path optical arrangement with velocity modulation have enabled us to observe 34 vibrationalndash;rotation transitions from 5094 to 4557 cmminus;1. Liquidhyphen;N2cooled plasmas were used for transitions involving low rotational levels, while gaseoushyphen;N2cooled plasmas were used for high rotational levels, up toJ,K=(9,9). From the relative intensities of the transitions, rotational temperature has been estimated to be sim;270 K for the former and sim;1300 K for the latter. The Dgr;Verbar;kminus;lVerbar;=plusmn;3 selection rule of the overtone band allows us to determine the absolute energy level values by combining the frequencies of the overtone band with those of the fundamental and hot bands.