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Ion-atom collisions

Ion-molecule collisions
Codes
Methods
Collisional systems

Codes

Our group is continuously developing or modifying computational codes that implement the different approaches suggested in the theoretical methods studied. With these codes, we can perform calculations of electronic excitation, single and double charge transfer, vibrational excitation, vibrationally-resolved charge transfer, vibrationally resolved electronic excitation, reactive and non-reactive charge transfer and ionization of atoms and molecules. The range of collisional energies goes from 1x10-3 to 1x106 eV/amu. Here we explain the details of the different codes:
  1. MELD, TCAM suit

    2. MELD is a gaussian-based system for ab initio calculation (QCPE: program 580, Indiana University) by E. R. Davidson and others.

    A modification of this program is employed to obtain electronic energies and non-adiabatic couplings. The molecular systems can be treated from SCF to MRCI level of theory.

    The TCAM suit is a set of scripts and Fortran programs that deal with joining and processing the information produced by the different modules of MELD, with the aim of automating the calculation of the different magnitudes (energies and couplings).

  2. SEIKON, QUAN

    3. These two programs are employed to obtain the cross section for the different processes of interest in a collision.

    SEIKON implements the semiclassical eikonal impact parameter method, with the possibility of using a vibrational-sudden treatment of the vibrational degree of freedom of the molecule involved in the collision.

    QUAN implements the "common reaction coordinate" formalism to obtain quantal cross sections.

    Both programs requiere potential energy curves and non-adiabatic couplings as input data.

  3. ClassicP

    4. This program implements the Classical trajectory Montecarlo method. It can deal with effective charge Coulomb potentials or with model potentials in order to represent the interaction of one electron with a complex ion.

  4. CTDIM

    5. Starting with a statistical description of the nuclear degrees of freedom of the hydrogen molecule, this program uses classical trajectories to simulate nuclear reaction dynamics. On top of that, a quantum mechanical description of the electronic part of the system is carried out in order to obtain charge transfer cross sections.

  5. Hcore, Pamnoor, Aguais

    6. These programs are used to produce pseudopotentials that represent the interaction of one electron with a complex target using one-electron wave functions. The collisional event is described using a set of asymptotically frozen molecular orbitals and the many-electron cross sections are optionally obtained using two models:

    1. The independent event model.
    2. By constructing approximated many-electron wave functions.
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