Welcome to XTDS’s documentation!

This is the documentation of version 2.0.

XTDS (Tensorial Spectroscopy Toolbox) is a cross-platform software suite for the analysis and simulation of high-resolution molecular spectra, using the tensorial formalism developed by the Dijon spectroscopy group for spherical and symmetric top molecules. With XTDS you can:

• create parameter files for the effective Hamiltonian and transition moment operators;

• calculate rovibrational energy levels and their vibrational mixings;

• calculate line lists of absorption (dipole), Raman (polarizability) and Stark spectra, in TDS or HITRAN format;

• simulate synthetic spectra under various physical conditions;

• fit the parameters of the models to experimental line positions and intensities;

• visualize the results: energy levels, stick spectra, synthetic spectra and observed minus calculated residuals.

XTDS is made of two parts. The computing engine consists of seven spectroscopy packages (STDS, HTDS, C2vTDS, C3vTDS, C3vsTDS, C4vTDS and D2hTDS), each one being a set of Fortran programs dedicated to a class of molecules. On top of them, a graphical interface written in Java creates the calculation jobs, runs them and displays their results, so that no knowledge of the underlying programs is required to get started.

XTDS works hand in hand with Spview, which is used to assign experimental spectra: the prediction files computed by XTDS are loaded into Spview, and the assignment files written by Spview are read by the XTDS fit jobs.

It is developed at the Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB, UMR 6303 CNRS — Université Bourgogne Europe) in Dijon, by the MARS group.

It’s free software, distributed under the GPLv3 license: you can change its source code and distribute your changes.