Parameter NERG
NERG is the number of total energies at which the calculation is to
be performed. Both the log-derivative and AIRY propagation are
significantly faster for the second and subsequent energies. Thus if cross
sections are desired over a range of energies, it is advantageous to set
NERG > 1.
The maximum value of NERG is controlled by a PARAMETER statement in the
subroutine LOGAIR (himain.f)
and can not exceed 25 (because of restrictions imposed by the length of
the names of the logical units reserved for storing the partial and
integral cross sections and selected S-matrix elements). If NERG>1, then
three scratch files (units 10-12) are opened to store the required energy
independent matrices as well as the channel quantum numbers.
The value of NERG can be changed with the command
If {newvalue} is larger than the value of NERG currently stored, then you
will be warned to increase accordingly the array of energies at which the
calculations are to be performed. This can be done with the command
ENERG={energy1},{energy2}...{energyn}\
where n is the new value of NERG. The string of input values must be
terminated with a backslash if other input occurs on the same line.
Alternatively, you can specify a grid of collision energies b the command
ENERG = {negative number},{energy1},{energ2},{nerg}
where
- energy1: The initial energy
- energy2: The final energy
- nerg: The number of energies (less than or equal to 25)
The spacing for the grid of energies is determined as
delta_e=(energ2-energ1)/nerg
This spacing is then rounded to the nearest 0.01 cm-1, so that the final energy
becomes
e_final=e_initial + (nerg-1)*delta_e
which may not be exactly equal to the final energy which you initially specified.
In all cases, the energy values are reordered in decreasing order, starting with the
highest value.
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