xyzQCT is a code devoted to Quassiclasical Trajectory Calculations (QCT). It implements several initial conditions preparation, such as normal modes and adiabatic switching, as well as propagation of trajectories in order to obtain fixed energy and temperature statistics.

To clone this repository the following command must be executed:

git clone --recurse-submodules git@github.com:pablomazo/xyzQCT.git

• Fortran compiler (the code has been tested with gfortran).
• LAPACK library.
• Compile the DDEABM library provided in the code. For that run:

make ddeabm

In order to use xyzQCT the code must be computed together with the potential energy surface (PES) routines.

xyzQCT will interact with the PES through two subroutines: setpotxyz and potxyz:

• setpotxyz: is called without arguments. This routine will be called at the very beginning of the xyzQCT execution and can be used to load any files or data the PES may require.
• potxyz(pos, ener, der): This routine receives a vector (pos) of dimension 3 * number of atoms and returns a float (ener) and a vector (der) of dimension 3 * number of atoms. pos contains the atomic coordinates of all the particles in the system is Bohr. ener is the energy for that configuration expressed in Hartree. der is the derivative of the energy wrt the positions (negative of the force) and it is expressed in Hartree/Borh.

The files related to the potential energy surface must be included in the Makefile under the variables PESdir and PES. For example, if the PES files are located in the folder /home/work/PES/system1 and it is composed of the file system1_pes.f90 then these variables would be set as:

PESdir=/home/work/PES
PES=$(addprefix $(PESdir), system1_pes.f90)

After setting these variables run make and the QCT.x executable should be created.

To run the code just execute the binary file QCT.x. It will automatically read the input file input.dat with the calculation setup. A file sal is generated with a log of the calculation. In this file the user can find all the available keys to control the code execution.

The folder examples contains several input.dat files for 3 common calculations: Adiabatic switching initial condition generation, and collisions to get statistics at constant energy and temperature.