Resonance Raman intensity analysis investigation of metal-metal bonded transitions: an examination of the (1)A(2u) <- (1)A(1g) (5d sigma* -> 6p sigma) transition of Pt-2(P2O5H2)(4)(4-)

A preliminary resonance Raman intensity analysis study of the (1)A(2u) <- ( 1)A(1g) (5d sigma* -> 6p sigma) transition of (n-Bu4N)(4)[Pt-2(P2O5H2)(4)] in acetonitrile solution at room temperature is reported. The absolute reso nance Raman and absorption intensities were simultaneously simulated using wavepacket calculations and a simple model. The best fit parameters indicat e that the Pt-Pt bond length changes by about 0.225 Angstrom in the initial ly excited (1)A(2u) state relative to the ground state. This is in good agr eement with previous studies on the vibronically structured absorption and emission spectra of low-temperature crystalline (n-Bu4N)(4)[Pt-2(P2O5H2)(4) ] which suggested that the Pt-Pt bond length changes by about 0.21 Angstrom in the 1,3A(2u) states. The resonance Raman intensity analysis demonstrate d here can be generally applied to metal-metal bonded electronic transition s for compounds and sample conditions (such as room temperature liquids for many samples) which do not exhibit any vibronic structure. Copyright (C) 1 999 John Whey & Sons, Ltd.