Picosecond Coherent Vibrational Spectroscopy (CARS) of a DNA-Intercalating Ru Complex

Vibrational spectra (1100−1800 cm-1) of the ground state and two excited electronic states, populated following the 5 ps, 440 nm excitation, of the [Ru(phen)2dppz]+2 (phen = 1,10-phenanthroline and dppz = dipyrido[3,2-a:2‘,3‘-c] phenazine) complex in aqueous solution are measured by coherent anti-Stokes Raman scattering (CARS). The band origin positions of vibrational features in the picosecond resonance CARS (PR/CARS) spectrum of ground state [Ru(phen)2dppz]+2 obtained with ω1 (probe) wavelengths of 491 and 530 nm are the same to within