Twohyphen; and threehyphen;photon absorption of iodine molecules via dissociative states

摘要

Iodine vapor was irradiated by focused dye laser light in the range of 450ndash;610 nm. Firstly, by irradiation of the laser light tuned near the dissociation limit of theBstate (sim;500 nm) emission bands were observed at 385, 342, 287, and 270 nm by twohyphen; or threehyphen;photon absorption. When the energy of laser light was above the dissociation limit of theBstate, the emission intensity decreased drastically but was still observed. No effect of polarization of the laser light (circular or linear) was observed, indicating that the twohyphen;photon absorption is consecutive absorption of photons via dissociative states. Secondly, the absorption tuned far below the dissociation limit of theBstate (550ndash;600 nm) led to occurence of 342, 325, and 270 nm emission bands and IR emission at 1.3 mgr;m originating from electronically excited iodine atoms Iast;(2P1/2). The excitation spectra of both UV and IR emission had the same threshold wavelength around 600 nm. The formation of the states responsible for the 325 and 270 nm bands is considered as threehyphen;photon absorption via the dissociative 0g+(1Sgr;) state that correlates to two Iast;(2P1/2) atoms.