  Single-beam spectrally controlled (SBSC) two-dimensional (2D) Raman
spectroscopy is a unique 2D vibrational measurement technique utilizing trains
of short pulses that are generated from a single broadband pulse by pulse
shaping. This approach overcomes the difficulty of 2D Raman spectroscopy in
dealing with small-signal extraction and avoids complicated low-order cascading
effects, thus providing a new possibility for measuring the intramolecular and
intermolecular modes of molecular liquids using fifth-order 2D Raman
spectroscopy. Recently, for quantitatively investigating the mode-mode coupling
mechanism, Hurwitz et al. [Optics Express 28, 3803 (2020)] have developed a new
pulse design for this measurement to separate the contributions of the fifth-
and third-order polarizations, which are often overlapped in the original
single-beam measurements. Here, we describe a method for simulating these
original measurements and the new 2D Raman measurements on the basis of a
second-order response function approach. We carry out full molecular dynamics
simulations for carbon tetrachloride and liquid water using an
equilibrium-nonequilibrium hybrid algorithm, with the aim of explaining the key
features of the SBSC 2D Raman spectroscopic method from a theoretical point of
view. The predicted signal profiles and intensities provide valuable
information that can be applied to 2D spectroscopy experiments, allowing them
to be carried out more efficiently.
