Methods are given for calculating matrix elements of an arbitrary two‐electron spin‐dependent operator, using wavefunctions based on open‐shell spin‐projected spin—orbital products. The formalism is developed both in terms of the entire spin space of the desired multiplicity and in terms of the projection operators discussed by Löwdin. The results are also specialized to the important case of orthogonal spatial orbitals. The methods are illustrated by application to the Fermi‐contact interaction.

1.
F. E.
Harris
,
Advan. Quantum Chem.
3
,
61
(
1966
).
2.
F. E.
Harris
,
Mol. Phys.
11
,
243
(
1966
).
3.
P.‐O.
Löwdin
,
Phys. Rev.
97
,
1509
(
1955
).
4.
R.
Pauncz
,
J.
de Heer
, and
P.‐O.
Löwdin
,
J. Chem. Phys.
36
,
2247
(
1962
).
5.
R.
Serber
,
Phys. Rev.
45
,
461
(
1934
);
R.
Serber
,
J. Chem. Phys.
2
,
697
(
1934
).
6.
T.
Yamanouchi
,
Proc. Phys.‐Math. Soc. Japan
20
,
547
(
1938
).
7.
M. Kotani, A. Amemiya, E. Ishiguro, and T. Kimura, Table of Molecular Integrals (Maruzen Co. Ltd. Tokyo, 1955).
8.
J. E.
Harriman
,
J. Chem. Phys.
40
,
2827
(
1964
).
9.
A.
Hardisson
and
J. E.
Harriman
,
J. Chem. Phys.
46
,
3639
(
1967
).
10.
F. E.
Harris
,
J. Chem. Phys.
46
,
2769
(
1967
).
11.
See, for example,
M.
Karplus
and
D. H.
Anderson
,
J. Chem. Phys.
30
,
6
(
1959
).
12.
P. A. M. Dirac, The Principles of Quantum Mechanics (Oxford University Press, Oxford, 1958), 4th ed., pp. 221ff.
13.
This formula is easily obtained from that given by
V. H.
Smith
,
J. Chem. Phys.
41
,
277
(
1964
).
14.
G. M.
Harris
and
F. E.
Harris
,
J. Chem. Phys.
31
,
1450
(
1959
).
15.
F.
Sasaki
and
K.
Ohno
,
J. Math. Phys.
4
,
1140
(
1963
).
16.
J. K.
Percus
and
A.
Rotenberg
,
J. Math. Phys.
3
,
928
(
1962
).
17.
F. E. Harris and V. H. Smith (unpublished).
This content is only available via PDF.
You do not currently have access to this content.