QTRANS.f is the fortran program that I use to transform the electric field gradient (efg) tensor from the standard orientation of the Gaussian output to the principal axes of the inertial tensor, and to the principal axes of the nuclear quadrupole coupling constant (nqcc) tensor.  Feel free to copy/paste the source code, but please inform me when you have done so: wbailey@kean.edu.
	Examples of Input / Output are given for water (C2V), isobutylnitrile (CS), and oxiranecarbochloride (C1).
	Please cite this program as "W. C. Bailey, Calculation of Nuclear Quadrupole Coupling Constants in Gaseous State Molecules, http://turbo.kean.edu/~wbailey/NQCC.html."
	I am indebted to Z. Kisiel for making freely available his QDIAG.f.  This program contains the subroutine JACK for matrix diagonalization, which is central to my program.
		Software.html
		Last modified: 22 Nov 2005