Rapid and Accurate Measurement
of the Frequency–Frequency
Correlation Function
- Publication date
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Abstract
Using an implementation of heterodyne-detected vibrational
echo
spectroscopy, we show that equilibrium spectral diffusion caused by
solvation dynamics can be measured in a fraction of the time required
using traditional two-dimensional infrared spectroscopy. Spectrally
resolved, heterodyne-detected rephasing and nonrephasing signals,
recorded at a single delay between the first two pulses in a photon
echo sequence, can be used to measure the full waiting time dependent
spectral dynamics that are typically extracted from a series of 2D-IR
spectra. Hence, data acquisition is accelerated by more than 1 order
of magnitude, while permitting extremely fine sampling of the spectral
dynamics during the waiting time between the second and third pulses.
Using cymantrene (cyclopentadienyl manganese tricarbonyl, CpMn(CO)<sub>3</sub>) in alcohol solutions, we compare this novel approachdenoted
rapidly acquired spectral diffusion (RASD)with a traditional
method using full 2D-IR spectra, finding excellent agreement. Though
this approach is largely limited to isolated vibrational bands, we
also show how to remove interference from cross-peaks that can produce
characteristic modulations of the spectral dynamics through vibrational
quantum beats