What is it ?

A small fortran (f03) program to calculate force constants (Bonds, Angles and Torsions) using Gaussian09 fchk parsed cartesian Hessian matrix.
See below for format.

Installation

Compile it with gfortran (>= 4.9) or ifort (>= 2013). Need LAPACK (call DGEEV)
Ex:
gfortran -framework Accelerate sem_forces.f09 -o sem_forces (using the MacOS default installed LAPACK framework)

Usage

Just lauch the program with the data file name as first argument
Ex: ./sem_forces dataH2O_MP2

Data file format

You can write a fchk parser.
The parsed file is the first argument when lauching the program

1: Number of Atoms
2: --------- Coordinates --------- (or blank line)
3: Number1;AtomicNumber1;X1;Y1;Z1 (in bohr)
4: Number2;AtomicNumber2;X2;Y2;Z2
...
.: --------- Constants --------- (or blank line)
.: Number1;Number1;Number1;Number2;Number2;Number2;...
.: AtomicNumber1;AtomicNumber1;AtomicNumber1;AtomicNumber2;AtomicNumber2;AtomicNumber2;...
.: AtomicSymbol1;AtomicSymbol1;AtomicSymbol1;AtomicSymbol2;AtomicSymbol2;AtomicSymbol2;...
.: x1;y1;z1;x2;y2;z2;...
.: Fx1x1;Fy1x1;Fz1x1;Fx2x1;... (in hartree/bohr^2)
.: Fx1y1;Fy1y1;Fz1y1;Fx2y1;...
.: Fx1z1;Fy1z1;Fz1z1;Fx2z1;...
...

Example included (dataXXX_XXX files).

License

Distributed under the MIT license