Dopplerhyphen;free high resolution laser spectroscopy of the Cs2Dthinsp;1Sgr;+ustate and the predissociation

摘要

A Dopplerhyphen;free polarization spectrum of theDthinsp;1Sgr;+u(vrsquo;,Jrsquo;)ndash;Xthinsp;1Sgr;+g(vlsquo;,Jlsquo;) transition has been observed, and the molecular constants of theDthinsp;1Sgr;+ustate were determined. A remarkable variation of the vibrational spacing Dgr;Gvwithvrsquo;, and large deviations of Dgr;Gvfrom the fitted Dgr;Gvcurve forvrsquo;gsim;35 were analyzed. The potential curve of the perturbing state, which was identified as the bound (2)3Pgr;ustate, was estimated. By using an experimental setup where a collimated cesium beam is crossed at right angles by the laser beam, we measured the excitation spectra by monitoring separately the molecular fluorescence and theD2orD1atomic emission. We found that a predissociation of theDthinsp;1Sgr;+ustate occurred forvrsquo;gsim;20, and the probability of predissociation increased withvrsquo;. The measuredvrsquo;andJrsquo;dependence of the linewidth Ggr; showed a significant increase forvrsquo;gsim;25. The predissociation of theDthinsp;1Sgr;+ustate is caused by a combination of spinndash;orbit interaction between theDthinsp;1Sgr;+u(vrsquo;Jrsquo;) and (2)3Pgr;0u(ethinsp;vJrsquo;) levels, and theLhyphen;uncoupling interaction between the bound (2)3Pgr;0u(ethinsp;vJrsquo;) and dissociativecthinsp;3Sgr;+u(N=Jrsquo;Jrsquo;) levels.