i_charge

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 THE VERSION 5.0 HAS BEEN DEVELOPED TO FIT
 PARTIAL ATOMIC CHARGES FOR MOLECULAR DYNAMICS
 SIMULATIONS FOR A VERIETY OF ORGANIC COMPOUNDS.
 A GRID OF ELECTROSTATIC POTENTIAL POINTS IS
 GENERATED FROM QM CALCULATIONS AND THESE
 POINTS ARE FITTED TO AN ATOM-CENTERED POINT
 CHARGE MODEL. PARTIAL ATOMIC CHARGES ARE THEN
 USED TO CALCULATE MOLECULAR MULTIPOLE MOMENTS.

 ELECTROSTATIC POTENTIAL POINTS THAT LAY WITHIN
 THE VAN DER WAALS ATOMIC SURFACES ARE EXCLUDED
 FROM THE FITTING TO AVOID CONTRIBUTION FROM
 EXCHANGE REPULSION AND CHARGE TRANSFER INTERACTIONS.

 A SQUARE MATRIX A IS BUILT AND THEN IT IS
 DECOMPOSED USING LU (A = L U) OR SVD (A = U W V)
 DECOMPOSITION TECHNIQUES. ONE OF THESE TWO TECHNIQUES
 CAN BE CHOISEN BY PUTING .true. VALUE IN the parameter.h FILE.

 CONSTRAINTS

 Any constraints imposed should be based on
 atom order number as it is listed in your
 cube file. The charge constrains should be
 imposed in a crossed closed way, see example below.