E 0g+approachesA 1u and E 0g+approachesBseconds or inches 1u laser-induced fluorescence in molecular iodine recorded by Fourier-transform spectroscopy

The E 0g+ - A 1u(3Πu) and E 0g+ - Bseconds or inches 1u(1Πu) fluorescence has been recorded at moderate resolution (0.150 cm-1) in the range 28600-31600 cm-1, using the direct optical-optical double resonance: E 0g+relata of a relationB 0u+relata of a relationX 0g+. Both the 1u states observed in fluorescence correlate with ground-state I atoms. The Ω-type doubling observed in these states is interpreted in terms of their interactions with the two 0u- states dissociating at the same limit. This is the first rotational analysis of the weakly bound Bseconds or inches 1u state. The equilibrium spectroscopic constants are Te=12344.804(40) cm-1, ωe=19.83(3) cm-1, Be=0.014607(11) cm-1 and re=4.265 A. The last observed vibrational level is vseconds or inches=20 which is located 0.978 cm-1 below the dissociation limit. The parameters describing the long-range part of the potential curve are De (Bseconds or inches 1u)=202.53(4) cm-1, C5=-0.49(28)x105 cm-1 A5, C6=1.00(33)x106 cm-1 A6, C8=0.40(6)x108 cm-1 A8. The last bound vibrational level is v=23-1+0. In addition a self-induced electronic collision transfer E 0+g(vminutes or feet,Jminutes or feet) - coll.D 0+u(vt,Jt) is observed with the strong propensity rule Jt=Jminutes or feet±1 and a vibrational propensity vminutes or feet-vt governed by the proximity of the resonance between the energy loss in D 0+u(vt,Jt) and the energy separation (Jseconds or inches-Jtseconds or inches∼0) of rovibrational levels of the X 0+g(vseconds or inches,Jseconds or inches) partner in the collision. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)