title: Population-controlled impulsive vibrational spectroscopy: background- and baseline-free Raman spectroscopy of excited electronic states.
abstract: We have developed the technique of population-controlled impulsive vibrational spectroscopy (PC-IVS) aimed at providing high-quality, background-free Raman spectra of excited electronic states and their dynamics. Our approach consists of a modified transient absorption experiment using an ultrashort (<10 fs) pump pulse with additional electronic excitation and control pulses. The latter allows for the experimental isolation of excited-state vibrational coherence and, hence, vibrational spectra. We illustrate the capabilities of PC-IVS by reporting the Raman spectra of well-established molecular systems such as the carotenoid astaxanthin and trans-stilbene and present the first excited-state Raman spectra of the retinal protonated Schiff base chromophore in solution. Our approach, illustrated here with impulsive vibrational spectroscopy, is equally applicable to transient and even multidimensional infrared and electronic spectroscopies to experimentally isolate spectroscopic signatures of interest.
authors.affiliation: Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Torsten
authors.initials: T
authors.lastname: Wende
authors.forename: Matz
authors.initials: M
authors.lastname: Liebel
authors.forename: Christoph
authors.initials: C
authors.lastname: Schnedermann
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Pethick
authors.forename: Philipp
authors.initials: P
authors.lastname: Kukura