2dIR

1d- and 2d-IR calculation in semi-classical line shape theory. Build in C++ with Python/Cython interface.

useage detail

See Readme in source/ and the test.py for example.

theory and computational tricks

See PDF file in note/

The basic formula for three-order non-linear spectroscopy is written as:

Where $R_r$ and $R_{nr}$ means rephasing and non-rephasing response function:

In semi-classical line shape theory, as an example, $R_3$ can be written as:

where $\mu_{ij}$, $\omega_{ij}$ is the corresponding transition dipole and transition frequencies, respectively, of i,j states of a given vibration mode. <...> is classical ensemble.

The main feature of this program is calculating $I$ with $\omega_{ij}(t)$ and $\mu_{ij}(t)$ as input.