			15min:

FTIR AND ULTRAFAST INFRARED SPECTROSCOPY OF THE DICYANAMIDE ANION IN SOLUTION.

KEVIN DAHL, GERALD M. SANDO AND JEFFREY C. OWRUTSKY, Chemistry Division, U.S. Naval Research Laboratory, Washington, DC 20375.

Steady state and time-resolved IR spectroscopy have been used to study the vibrational band positions, vibrational energy relaxation (VER) rates, and reorientation times of the antisymmetric C equiv N stretching band of dicyanamide (N(CN)₂^-) anion near 2100 cm^-1 in several bulk solvents. The transient signals indicate a complicated relaxation mechanism, consistent with there being a Fermi resonance enhanced combination band in the region. The solvent-induced spectral blue shifts and VER rates both increase for solvents with stronger solute-solvent interactions. The gas-phase vibrational frequency is estimated by extrapolating to zero solvent shift by scaling the solvent shift to those previously observed for azide (N₃^-). N(CN)₂^- exhibits a strong correlation between vibrational frequency and VER rate, so that, as with N₃^-, an estimate of the relative VER rate can be obtained from the static spectra.