# Matrix elements of lx,ly,lz

Girts Barinovs girts at kfi.lu.lv
Fri Mar 7 12:11:28 GMT 2003

```Dear all!

I am calculating matrix elements of the angular momentum
operators lx, ly, lz. Strangely, the results at CI level
change if I calculate or do not calculate the matrix
elements at CASSCF level before doing CI calculations.
I would like to have some control of this behavior,
could anybody help me to understand what is happening
in my calculations. Thanks.
Girts

****************************************************************************

***,CH2+

geometry={X;noorient;                       !z-axis goes through C and mass center
C, -1,0.00000000, 0.00000000,  1.150513890; !yz-molecule plane, Cs symmetry
H1,-1,0.00000000, 0.315000000,-7.395082115; !0,0,0 -center of mass
H2,-1,0.00000000,-0.315000000,-6.303890106;}!Jacobi R=8,r=1.26,theta=30

basis
H=VTZ
C=VQZ
end

hf;occ,4,0;wf,7,1,1

multi;occ,4,1;core,1,0;wf,7,1,1;wf,7,2,1;
!tran,lx,ly,lz; !<====!!! Different CI results if comment or uncomment this line

ci;occ,5,2;core,1,0;wf,7,1,1;save,7001.1;
ci;occ,5,2;core,1,0;wf,7,2,1;save,7002.1;

ci;trans,7002.1,7001.1,lx,ly,lz;

table,r1(1),rhq(i),trlz(1),trly(1),sqrt(trlz(1)**2+trly(1)**2)
!Square root of the sum above is expected to be equal to 1 approximately.

****************************************************************************
Output of
tran,lx,ly,lz;
...
ci;trans,7002.1,7001.1,lx,ly,lz;

R1(1)   RHQ(I)     TRLZ(1)       TRLY(1)   SQRT(TRLZ(1)**2+TRLY(1)**2)
R1(1)   RHQ(I)   0.85721515   -0.51487382                   0.99995643

MRCI            MRCI            MULTI           MULTI           HF-SCF
-38.54145104    -38.54145010    -38.44314750    -38.44316943    -38.42124983
****************************************************************************
Output of
ci;trans,7002.1,7001.1,lx,ly,lz;

R1(1)   RHQ(I)         TRLZ(1)      TRLY(1)   SQRT(TRLZ(1)**2+TRLY(1)**2)
R1(1)   RHQ(I)   2.54906962D-05   0.17017114                   0.17017114

MRCI            MRCI            MULTI           MULTI           HF-SCF
-38.54145104    -38.54145010    -38.44314750    -38.44316943    -38.42124983
****************************************************************************

I am using molpro2000.1

```