- Email: [email protected]
A program for calculating the static interaction potential between an electron and a diatomic molecule
C-90 COMPUTER PHYSICS COMMUNICATIONS 2 (1971) 261-271. N O R T H - H O L L A N D PUBLISHING COMPANY
A
PROGRAM
POTENTIAL
FOR
BETWEEN
CALCULATING AN
THE
ELECTRON
STATIC
AND
INTERACTION
A DIATOMIC
MOLECULE
F. H. M. F A I S A L
National Aeronautics and Space A d m i n i s t r a t i o n , Goddard Space Flight Center, Greenbelt, Maryland 20771, USA A. L. V. T E N C H
Theoretical P h y s i c s Division, A t o m i c Energy R e s e a r c h Establishment, Harwell, Didcot, B e r k s h i r e , UK Received 16 M a r c h 1971 R e v i s e d m a n u s c r i p t r e c e i v e d 7 May 1971
PROGRAM
SUMMARY
Title of program : STATIC INTERACTION POTENTIAL Catalogue number: ACQW Computer: IBM 360/75. Installation: A.E.R.E. Harwell Operating s y s t e m or monitor under which the program is executed: HASP M F T 2 P r o g r a m m i n g languages used: FORTRAN IV High speed store required: 52K words. N o . o f bits in a word: 32 Is the program overlaid? Yes No. o f magnetic tapes required: None What other peripherals are u s e d ? C a r d r e a d e r ; Line p r i n t e r ; Disc IBM 2311; Data cell IBM 2314 N u m b e r of cards in combined program and test deck: 1800 K e y w o r d s descriptive of problem and method of solution: Quantum C h e m i s t r y , Molecular, Wavefunction, SingleCentre Expansion, Static Potential, Dipole Moment, Quadrupole Moment, C l e b s c h - G o r d a n Coefficient
Nature o f the physical problem
R e s t r i c t i o n s on the complexity o f the program
T h i s p r o g r a m c a l c u l a t e s the s i n g l e c e n t r e multipole expansion of the s t a t i c potential for a diatomic m o l e cule. It a l s o c a l c u l a t e s the dipole and quadrupole m o m e n t s . It p r o v i d e s wavefanctions and the s t a t i c potential in a f o r m suitable for u s e in the companion p r o g r a m by Sinfaflara [1].
The p r o g r a m is limited to an extended b a s i s s e t of 50 t e r m s , and a m a x i m u m s h e l l n u m b e r of 4.
Method of solution The m o l e c u l a r o r b i t a l s a r e a s s u m e d to be given by an LCAO MO SCF wavefunction obtained f r o m a b a s i s s e t of S l a t e r - t y p e AO's around the 2 nuclei of the m o l e c u l e . T h e s e a r e expanded in L e g e n d r e p o l y n o m i a l s around the c e n t r e of m a s s . The r e s u l t i n g wavefunctions a r e n o r m a l i s e d and u s e d to calculate the s t a t i c potential.
Typical running t i m e To evaluate a s e t of MO at 1 value of r takes about ½ s e c on the IBM 360/75. Similarly to evaluate a s e t of s t a t i c potentials at I value of r t a k e s about ½ s e c .
Reference [1] A. L. Slnfallam, C o m p u t e r P h y s . Commun. 1 (1970) 445.
A
PROGRAM
POTENTIAL
FOR
BETWEEN
CALCULATING AN
THE
ELECTRON
STATIC
AND
INTERACTION
A DIATOMIC
MOLECULE
F. H. M. F A I S A L
National Aeronautics and Space A d m i n i s t r a t i o n , Goddard Space Flight Center, Greenbelt, Maryland 20771, USA A. L. V. T E N C H
Theoretical P h y s i c s Division, A t o m i c Energy R e s e a r c h Establishment, Harwell, Didcot, B e r k s h i r e , UK Received 16 M a r c h 1971 R e v i s e d m a n u s c r i p t r e c e i v e d 7 May 1971
PROGRAM
SUMMARY
Title of program : STATIC INTERACTION POTENTIAL Catalogue number: ACQW Computer: IBM 360/75. Installation: A.E.R.E. Harwell Operating s y s t e m or monitor under which the program is executed: HASP M F T 2 P r o g r a m m i n g languages used: FORTRAN IV High speed store required: 52K words. N o . o f bits in a word: 32 Is the program overlaid? Yes No. o f magnetic tapes required: None What other peripherals are u s e d ? C a r d r e a d e r ; Line p r i n t e r ; Disc IBM 2311; Data cell IBM 2314 N u m b e r of cards in combined program and test deck: 1800 K e y w o r d s descriptive of problem and method of solution: Quantum C h e m i s t r y , Molecular, Wavefunction, SingleCentre Expansion, Static Potential, Dipole Moment, Quadrupole Moment, C l e b s c h - G o r d a n Coefficient
Nature o f the physical problem
R e s t r i c t i o n s on the complexity o f the program
T h i s p r o g r a m c a l c u l a t e s the s i n g l e c e n t r e multipole expansion of the s t a t i c potential for a diatomic m o l e cule. It a l s o c a l c u l a t e s the dipole and quadrupole m o m e n t s . It p r o v i d e s wavefanctions and the s t a t i c potential in a f o r m suitable for u s e in the companion p r o g r a m by Sinfaflara [1].
The p r o g r a m is limited to an extended b a s i s s e t of 50 t e r m s , and a m a x i m u m s h e l l n u m b e r of 4.
Method of solution The m o l e c u l a r o r b i t a l s a r e a s s u m e d to be given by an LCAO MO SCF wavefunction obtained f r o m a b a s i s s e t of S l a t e r - t y p e AO's around the 2 nuclei of the m o l e c u l e . T h e s e a r e expanded in L e g e n d r e p o l y n o m i a l s around the c e n t r e of m a s s . The r e s u l t i n g wavefunctions a r e n o r m a l i s e d and u s e d to calculate the s t a t i c potential.
Typical running t i m e To evaluate a s e t of MO at 1 value of r takes about ½ s e c on the IBM 360/75. Similarly to evaluate a s e t of s t a t i c potentials at I value of r t a k e s about ½ s e c .
Reference [1] A. L. Slnfallam, C o m p u t e r P h y s . Commun. 1 (1970) 445.