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Purpose: calculate reaction probability with the Tannor-Weeks
         method (see JCP 110 (1999) 2761.)
 
Usage: twprob [ -o -F -e -p -t -h -? ]
                emin emax unit file edstr1 edstr2
 
Options:
 -o FILE: filename for output
 -F x   : multiply output with a factor x
 -e R U : shift energy scale in output by value R in units U
 -p I   : number of energy points is I (default: 500)
 -t tcut : read crosscorrelation function only up to T=tcut
 -cos n  : multiply crosscorr.function with cos(pi/2*t/T))**n
 -exp tau: multiply crosscorr.function with exp(-t/tau)
 -exp2 tau:multiply crosscorr.function with exp(-(t/tau)**2)
 -[h?]  : print this help text
 
"emin" and "emax" together with "unit" determine the energy
range of the output.
"file" contains the time-dependent overlap of the propagated
WF with a reference WF (output of crosscorr).
"edstr[12]" are files that contain the energy distributions of
the two WFs. This can be an enerd file, or any other file, in
which case the distribution is determined by columns 1 and 2
(useful for autospec/cspec/flux files). If an energy 
distribution is omitted, it is replaced by a constant of 1.0.

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