1      FUNCTION HELECT(N,P,H,F)
2      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
3      DIMENSION P(*), H(*), F(*)
4C***********************************************************************
5C
6C    SUBROUTINE CALCULATES THE ELECTRONIC ENERGY OF THE SYSTEM IN EV.
7C
8C    ON ENTRY N = NUMBER OF ATOMIC ORBITALS.
9C             P = DENSITY MATRIX, PACKED, LOWER TRIANGLE.
10C             H = ONE-ELECTRON MATRIX, PACKED, LOWER TRIANGLE.
11C             F = TWO-ELECTRON MATRIX, PACKED, LOWER TRIANGLE.
12C    ON EXIT
13C        HELECT = ELECTRONIC ENERGY.
14C
15C    NO ARGUMENTS ARE CHANGED.
16C
17C***********************************************************************
18      ED=0.0D00
19      EE=0.0D00
20      K=0
21      NN=N+1
22      DO 20 I=2,NN
23         K=K+1
24         JJ=I-1
25         ED=ED+P(K)*(H(K)+F(K))
26         IF (I.EQ.NN) GO TO 20
27         DO 10 J=1,JJ
28            K=K+1
29   10    EE=EE+P(K)*(H(K)+F(K))
30   20 CONTINUE
31      EE=EE+.5D00*ED
32      HELECT=EE
33      RETURN
34C
35      END
36