T2 selective scanning vibrational echo spectroscopy

Abstract

Experiments are presented on a mixture of tungsten hexacarbonyl (W(CO) 6) and (acetylacetonato)dicarbonylrhodium(I) (Rh(CO) 2acac) in liquid dibutylphthalate (DBP) in which the spectrum of the asymmetric CO stretching modes (∼2000 cm −1) is taken by continuously scanning the frequency of a ps vibrational echo pulse sequence and observing the vibrational echo intensity. While the absorption spectrum shows a large solvent background with DBP vibrational peaks, the vibrational echo spectrum is background free and contains only the W(CO) 6 and Rh(CO) 2acac peaks. When the delay between the vibrational echo pulses is changed, the ratio of the W(CO) 6 and Rh(CO) 2acac peaks changes because of differences in their homogeneous dephasing times.