THE ESTIMATION OF C-O BOND-LENGTH CHANGES IN THE EXCITED-STATES OF TRANSITION-METAL CARBONYLS

Advances in vibrational spectroscopy have led to increased knowledge o f shortlived excited states. In the case of transition metal carbonyl compounds, time-resolved infrared spectra can be measured directly. Th e C-O energy factored force constants are used to estimate the C-O bon d length distortions upon excitation. The new empirical relationship r (CO) = 1.674 - 0.184 In k(CO) allows excited state C 0 bond lengths to be calculated with a standard deviation of +/-0.005 angstrom. For ene rgy factored systems it is deemed unnecessary to calculate pseudodiato mic frequencies (nu(PD)) from the potential energy distribution.