Programs for Real Wavepacket Propagation
Exact Calculations using Real Wavepacket propagation
This is an exact calculations using real wavepacket. One can do this calculations using MCTDH input/operator file (for exact calculations) with little modifications. In the run section 'realwp' keyword need to use, which will generate initial real wavepacket from MCTDH exact complex wavepacket. Other things in the run section will be like exact calculations in MCTDH program. But right now it calculate only reaction probability using flux operator. Use probrw for calculating probability. For more details about real wavepacket dynamics referred to S. K. Gray J. Chem. Phys. 96, 6543(1992), Gray et al. J. Chem. Phys. 108, 950(1998), Hankel et al J. Chem. Phys. 125, 164303(2006). Please email to Dr Anthony J. H. M. Meijer (a.meijer@sheffield.ac.uk) for any problem in using.
Operator Section
Energy cut-off (V < R only) is essential here. Which will set maximum to R for potential energy, total rotational terms (means j12 + j22+...+jcent+K2) and Coriolis-coupling terms, separately. Similar way this will use the minimum for Coriolis-coupling term(s), if you have any. We have to do this to make sure the eigen values of Hamiltonian operator of the system are in -1.0 to +1.0 range.
Since we are using real wavepacket for propagation we could not use CAP, we use real function (Gray et al J. Chem. Phys. 91, 7671(1989), keyword DAMP, to damp the wavefunction at the edge of the grid. Calculation of flux operator is carried out analytically only for wrapped sinc DVR basis, keyword fluxws. So, one need to use wrapped sinc DVR basis for coordinate along which flux to be calculated.
Integrator Section
One need to give maximum and minimum value of the Hamiltonian to
shift and scale the Hamiltonian(Tal-Ezer et al J. Chem. Phys.
81, 3967(1984), H --> f(H), keyword hscale
= E_min, E_max. From experience it is found that the difficult
job to define E_min and E_max. One need to
calculate wavefunction at t=1 from t=0 using Chebychev iteration to
start the integration, for that need to define number of Chebychev
iteration, keyword ncheb=N. To calculate the flux we have
to provide a number (fluxsave) (every fluxsave
time steps it will be calculating flux), energy window
(femin,femax) and number of energy points (prne)
for calculating Probability. Fluxsave number will be
modified by the energy window used for calculating the probability.
Keyword for this eprob = fluxsave, prne, femin, femax