#! /bin/awk -f
#
# Author: Michael Seth
# Added to Database: 7/02/05
#
# Purpose: Calculates the vibrational entropy of a series of harmoic
# oscillators as is done in a standard frequency analysis. 
#
# To run: Vibent input.in
#
# input.in has one line for each vibration containing the vibrational
# frequency in cm-1 and the temperature in K.
# e.g.
#
#     1800.0   293.0
#     2800.0   293.0   
#
{total += 8.31451*log(1/(1-exp((-1*$1*11.9626582)/(8.31451*$2))));
 T1=($1*11.9626582)*exp((-1*$1*11.9626582)/(8.31451*$2))/((1-exp((-1*$1*11.9626582)/(8.31451*$2))));
 T1=T1/$2;
 total += T1;
print "Vib. entropy of vibration ",NR," in kJ/molK ",T1
#print 8.31451*log(1/(1-exp((-1*$1*11.9626582)/(8.31451*$2)))),
#($1*11.9626582)*exp((-1*$1*11.9626582)/(8.31451*$2))/((1-exp((-1*$1*11.9626582)/(8.31451*$2)))),T1 }
}
END {print  "Total Ent. in kJ/molK ",total, " in kcal/molK",total/4.184}