last modified: 01-DEC-1975 | catalog | categories | new | search |

NESC0632 MMM3

MMM-3, Semi Rigid Molecule Normal Modes and Frequencies for Slow Neutron Scattering Calculation

top ]
1. NAME OR DESIGNATION OF PROGRAM:  MMM3
top ]
2. COMPUTERS
To submit a request, click below on the link of the version you wish to order. Only liaison officers are authorised to submit online requests. Rules for requesters are available here.
Program name Package id Status Status date
MMM-3 NESC0632/01 Tested 01-DEC-1975

Machines used:

Package ID Orig. computer Test computer
NESC0632/01 IBM 370 series IBM 370 series
top ]
3. DESCRIPTION OF PROBLEM OR FUNCTION

MMM3 computes the eigenvalues
(frequencies)  and eigenvectors  (normal modes)  for a  semi-rigid
molecule, and  computes the  transformation matrix  for expressing
the Cartesian  displacements of the atoms  in terms of  the normal
coordinates.  Computation of the effective atomic masses and mean-
squared amplitudes of vibration for use in slow neutron scattering
calculations is included as well.
top ]
4. METHOD OF SOLUTION

The procedure centers around the manipulation
of matrices: 1)  the force constant matrix,  2) the transformation
matrix which describes  changes in bond angles  and distances, and
3)  the  new coordinate  matrix.   In  formulating a  problem  for
solution, the group  vibration method is used, i.e.  a molecule is
divided into groups  of atoms with each  atom in one and  only one
group, and  the motion  of each atom  is described  as the  sum of
displacements within  a group (intragroup motions),  together with
translational and rotational  motions of the groups  considered as
rigid units (skeletal motions).
top ]
5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Matrices      with
dimensions up to 55 x 55 are acceptable.
top ]
6. TYPICAL RUNNING TIME

3  seconds  are  required  to  execute  the
sample problem.
top ]
7. UNUSUAL FEATURES OF THE PROGRAM

The  group   vibration  approach
systematizes and simplifies preparation of the input data.
top ]
8. RELATED AND AUXILIARY PROGRAMS:
top ]
9. STATUS
Package ID Status date Status
NESC0632/01 01-DEC-1975 Tested at NEADB
top ]
10. REFERENCES
NESC0632/01, included references:
- D. H.  Speas:
Matrix  Routine for  Calculating Normal Modes, Frequencies,  and
Atom Displacements in  Molecules, Aerojet
Nuclear Company Program Description No. P00320, August 1964.
-  H. L.  McMurry:
A  Simplified Group Vibration Method for Calculating Normal Vibrations
of Large Molecules,
Spectrochimica Acta, Vol. 21, pp. 2091-2103, 1965.
- H. L. McMurry  and D. Speas:
Vibrational  Analysis of Propane  and   Its  Symmetrical  Deuterium
Substituted  Isomers,
Spectrochimica Acta, Vol. 21, pp. 2105-2117, 1965.
top ]
11. MACHINE REQUIREMENTS:  300K bytes of memory
top ]
12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NESC0632/01 FORTRAN-IV
top ]
13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:   OS/360.
top ]
14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

  If a
degeneracy exists,  the eigenvalues are calculated  correctly, but
the  eigenvectors may  be  wrong  unless special  precautions  are
employed in formulating the problem.  The procedure to be followed
in such cases is given in the program instructions.
top ]
15. NAME AND ESTABLISHMENT OF AUTHORS

                 H. L. McMurry and D. H. Speas
                 EG&G Idaho, Inc.
                 P. O. Box 1625
                 Idaho Falls, Idaho  83401
top ]
16. MATERIAL AVAILABLE
NESC0632/01
File name File description Records
NESC0632_01.001 SOURCE PROGRAM 527
NESC0632_01.002 SAMPLE PROBLEM DATA 258
NESC0632_01.003 SAMPLE PROBLEM PRINTED OUTPUT 829
top ]
17. CATEGORIES
  • W. Physics

Keywords: eigenvalues, eigenvectors, lattice vibrations, molecules, scattering.