WaveMixings.jl: A Julia Package for Computing Time-Resolved Nonlinear Electronic Spectra from on-the-Fly Quasi-Classical Trajectories

We present an efficient numerical implementation of the quasi-classical doorway-window approximation, specifically designed for on-the-fly simulations of time-resolved nonlinear spectroscopic signals, in the Julia package WaveMixings.jl. The code takes as input quasi-classical trajectory data (energies of electronic states and transition dipole moments between elecronic states) as a function of discretized time, which may be provided by any nonadiabatic quasi-classical dynamics package. The output of WaveMixings.jl are raw spectroscopic data, that is, spectral intensities as functions one or more frequencies and pump-probe delay time. The package contains modules that facilitate standard tasks such as input/output data handling, data filtering, and postprocessing, among others. WaveMixings.jl includes implementations of various signals, including integral and dispersed transient absorption pump-probe signals, time- and frequency-resolved fluorescence spectra, and two-dimensional electronic spectra. By developing WaveMixings.jl we aim to create a versatile platform to perform simulations and develop new methodologies within the quasi-classical doorway-window framework. WaveMixings.jl differs from other existing codes for the simulation of nonlinear time-resolved spectra by the explicit inclusion of the shapes and durations of the laser pulses.