Journal of Physical Chemistry A, Vol.104, No.16, 3508-3520, 2000
Resonant Raman, hot, and cold luminescence of iodine in rare gas matrixes
Spontaneous light emission (SLE) spectra induced by continuous wave excitation of iodine in rare gas matrixes is analyzed from the perspective of semiclassical molecular dynamics. The three-time correlation functions that describe the process are interpreted in terms of time circuits, where the reversibility of mechanics along specified paths establishes the distinction between resonant Raman (RR) and fluorescence. The observed hot luminescence (fluorescence from the vibrationally over-damped period of dynamics) is simulated, and the underlying dynamics analyzed to describe vibrational dephasing, formation of stationary states, and predissociation of I-2(B) in matrixes. The extracted predissociation time of 3-5 Ds in matrixes agrees with time-domain measurements. The analysis allows the interpretation of liquid phase spectra which contain both structured and unstructured SLE as strictly RR, suggesting that the unstructured component is due to linear complexes. The spectra also contain vibrationally relaxed emissions from the cage-bound, doubly spin-orbit excited I*I* states, which are prepared via sequential two-photon excitation with an intermediate state lifetime of 2 ms, assigned to A(P-3(1u)). The two main emission bands, which shift by 300 cm(-1) in proceeding from Ar to Kr to Xe, are assigned to I*I*(l(u))--> I-2(a(1g)), and I*I*:(0(g)(+))--> I-2(B "(l(u))) transitions, and analyzed.