Overview#
rotsim2d is a library to model two-dimensional infrared (2DIR) rovibrational spectra. It uses density-matrix perturbation theory treatment of nonlinear spectroscopy [1]. It assumes explicit time-ordering of interactions, i.e. it is suitable for time-domain spectroscopy with time-separated optical pulses.
Module rotsim2d.pathways contains classes and functions to produce and
manipulate trees of states that represent all possible nth order dipole
excitations starting from some molecular ground state.
A specific pathway (a double-sided Feynmann diagram) can be represented by rotsim2d.dressedleaf.Pathway from
rotsim2d.dressedleaf, which also allows to calculate the
polarization-angular momentum coupling factor for the pathway.
An abstract pattern of excitations can be attached to some specific molecular vibrational
mode by a rotsim2d.dressedleaf.DressedPathway instance.
At this level, one can produce a 2D map of resonance peaks (see rotsim2d.dressedleaf.Peak2D, rotsim2d.dressedleaf.Peak2DList) without calculating line shapes or explicit time dependence.
Module rotsim2d.propagate provides classes and functions for generating
actual time-dependent or frequency-domain experimental signals.
rotsim2d.visual provides convenience functions to visualize 2D
peak maps, 2D spectra and double-sided Feynmann diagrams with LaTeX/TikZ.
Modules rotsim2d.symbolic.functions and rotsim2d.symbolic.results
provide SymPy expressions and functions used to derive polarization and angular
momentum dependence of four-fold dipole interaction operator.
Actual data on vibrational modes of real molecules is provided by molspecutils package, which (so far) wraps data from the HITRAN database [2].
Footnotes