Experimental Studies for a New Family of Infrared Four-Wave Mixing Spectroscopies

Abstract

Vibrationally enhanced infrared and vibrationally enhanced Raman four-wave mixing spectroscopy are experimentally explored with the use of several model systems. Studies involving a mixture of chlorobenzene, dichlorobenzene, and deuterobenzene were performed to see whether a simultaneous resonance of a combination band could enhance the Raman ring breathing mode. The results show strong interference effects that may be responsible for a suppression of the Raman resonances. Studies were also carried out in systems of chloroform/deuterobenzene and hexane/deuterobenzene. The latter samples showed intensity increases and line-shape changes that are consistent with vibrational enhancement. The discovery of these enhancements form the basis for developing infrared four-wave mixing as a method for extracting new information about molecular vibrations.

An Introduction to Coherent Multidimensional Spectroscopy

“…For example, one of the first coherent 2D vibrational spectrometers used two separate tunable IR beams, a fixed wavelength visible beam to convert the signal to the visible region, and a monochromator with a PMT for coherent 2D vibrational spectroscopy. 58 This instrument was an extension upon the designs of earlier spectrometers used for coherent electronic spectroscopy where all four beams were in the visible or UV region. 59 A more recent high-resolution coherent 2D spectrometer uses one narrowband tunable pulse, two broadband pulses, and a monochromator equipped with a CCD.…”

“…For example, one of the first coherent 2D vibrational spectrometers used two separate tunable IR beams, a fixed wavelength visible beam to convert the signal to the visible region, and a monochromator with a PMT for coherent 2D vibrational spectroscopy. 58 This instrument was an extension upon the designs of earlier spectrometers used for High-resolution coherent 2D spectroscopy (top left) involves one narrowband beam and three broadband beams, while high-resolution coherent 3D spectroscopy (top middle) involvers two narrowband and two broadband beams. All beams are broadband for the impulsive technique, and its temporal sequence of laser pulses is shown on the bottom right, where the resulting signal can be recorded as function of any of the three time delays (t1, t2, and t3).…”

Experimental Determinations of Coherent Multidimensional Vibrational Spectroscopy

“…[16][17][18][19][20][21][22] Although there are many approaches for achieving coherent multidimensional vibrational spectroscopy (CMDVS), the strategy for creating the vibrational resonances in this work are diagrammed in Figure 1a. There are two processes that drive doubly vibrationally enhanced (DOVE) FWM-DOVE-IR and DOVERaman.…”

Coherent multidimensional vibrational spectroscopy

“…Experimentally, it is also important to consider the spatial dependence of the non-linear polarization and the ®elds [2,3,87,89,111]. The non-linear polarization and the electromagnetic ®eld that it launches have di erent spatial modulations that are characterized by the wavevectors.…”