MOLPRO

54 THE TDHF AND TDKS PROGRAMS 374
output (0=normal output, 1=object linear in matrices, 2=matrices as well, > 2 debug). The
subcommand PULSE determines the envelope used, and takes several options depending on the
envelope selected. Possibilities are:
NONE: no pulse, no options
STEP, e x ,e y ,e z , length
a DC-field of strength e q is applied in the qth direction for a total time
length (in au)
DC, e x ,e y ,e z ,α
a DC-field of strength e q is applied in the qth direction. The field is
switched on exponentially with a rate determined by α.
TRAP, e x ,e y ,e z ,ω,α
an oscillating field of strength e q is applied in the qth direction. The
field oscillates with angular frequency ω. The envelope reaches e q in
one period of the field, stays constant for α periods and then decays
to zero in one period.
CW, e x ,e y ,e z ,ω
an oscillating field of strength e q is applied in the qth direction. The
field oscillates with angular frequency ω. No envelope present.
CWSIN, e x ,e y ,e z ,ω,α
an oscillating field of strength e q is applied in the qth direction. The
field oscillates with angular frequency ω and is switched on using a
sin 2 envelope, where α determines how fast the field is switched on.
CWGAUSS, e x ,e y ,e z ,ω,α
like CWSIN, but with a Gaussian envelope
The finite pulses TRAP and STEP produce an absorption spectrum obtained from the timedependent
dipole moment sampled after the field is switched off. It is located in ($input).spec,
or in molpro.spec when running interactively, and contains of 4 columns, which contain energy
(eV) and the absorption in the x,y,z direction respectively.
All runs produce a file ($input).dat (or molpro.dat) which contains time-dependent properties,
like the components of the field, components of the dipole moment, total energy, orbital occupation
numbers, orbital energies and total number of electrons. The Molpro output file specifies
the order of the data in the file. For very long runs the size of the file is restricted by printing
only every twentieth set of data.
In case of an unrestricted run three files are produced: ($input).dat, ($input)a.dat, ($input)b.dat.
The first file contains the generic data about the field, total energy, dipole moments and the
expectation value of the total spin operator. The other two files contain the orbital energies and
occupation numbers for the α and β electrons respectively.
TDKS and TDUKS use the options provided by the KS and UKS comands. At the moment
TDKS/TDUKS suffers from numerical instabilities when using strong fields. Divergence of the
energy is observed, possibly due to the use of quadrature for the evaluation of the potential.
Quantum currents will be calculated when choosing ng > 2. A cubic grid will be computed of
size grsize with a total of ng 3 gridpoints. The imaginary part of the density will be summed at
every timestep and after the dynamics the total current will be evaluated at every gridpoint. The
user can extract the required data from this array by printing out parts of it, or by integrating
over point, but this requires actual coding, as this has not been implemented sufficiently neat. It
is also straightforward to evaluate the currents at every timestep or at selected timesteps. This is
not done automatically, because it slows down the dynamics considerably.