  This companion paper to [D. Picconi et al., J. Chem. Phys. 150 (2019)]
presents quantum dynamical simulations, using the Gaussian-based
multiconfigurational time-dependent Hartree (G-MCTDH) method, of time-resolved
coherent Raman four-wave-mixing spectroscopic experiments for the iodine
molecule embedded in a cryogenic crystal krypton matrix. These experiments
monitor the time-evolving vibrational coherence between two wave packets
created in a quantum superposition (i. e. a 'Schr\"odinger cat state') by a
pair of pump pulses which induce electronic $B\ ^3\Pi_u\left(0^+\right)
\longleftarrow X\ ^1\Sigma_g^+$ transitions.
  A theoretical description of the spectroscopic measurement is developed,
which elucidates the connection between the nonlinear signals and the wave
packet coherence. The analysis provides an effective means to simulate the
spectra for several different optical conditions with a minimum number of
quantum dynamical propagations. The G-MCTDH method is used to calculate and
interpret the time-resolved coherent Raman spectra of two selected initial
superpositions for a $\mathrm{I_2 Kr_{18}}$ cluster embedded in a frozen Kr
cage. The time- and frequency-dependent signals carry information about the
molecular mechanisms of dissipation and decoherence, which involve vibrational
energy transfer to the stretching mode of the four 'belt' Kr atoms. The details
of these processes and the number of active solvent modes depend in a
non-trivial way on the specific initial superposition.
