Difference between revisions of "CamCASP/Programming/4"
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# Molecules rotated and MOs calculated in already rotated geometry. |
# Molecules rotated and MOs calculated in already rotated geometry. |
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These should be equivalent. And the MOs should be equivalent and related by a Wigner rotation matrix. This was not the case and I found small, but noticable differences that led to small differences in the e-n energies (there should also be differences in the e-e energies, but I still have to trace other errors here, so cannot be sure). |
These should be equivalent. And the MOs should be equivalent and related by a Wigner rotation matrix. This was not the case and I found small, but noticable differences that led to small differences in the e-n energies (there should also be differences in the e-e energies, but I still have to trace other errors here, so cannot be sure). |
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| + | We should have had the following: |
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| + | # Same e-n energies. But these were -4966220.470061 CM-1 and -4966223.294960 CM-1 for the two methods. The differences are small, but they should not be present. Also, they are small compared with the e-n energy (this was the electrons of the rotated water with the nuclei of the un-rotated partner) but there should be *no* difference! Also, the n-n energy was the same in both cases. So the geometries are identical to a very good precision. |
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| + | # In this test, I had used only s-functions in the auxiliary basis. So |
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Revision as of 16:41, 5 May 2009
CamCASP => Programming => Rotations
The theory of integral and MO rotations has been described in The DF INTEGRAL module . This is a collection of odds and ends related to rotations.
DALTON
MOs from DALTON don't seem to be rotationally invariant. Consider the following example:
water dimer. Sadlej/PBE0/AC MC basis type. Aux basis: JK-tzvpp. Geom: R=2.4 Ang in min-orientation.
I noticed a discrepancy in the e-e and e-n energies (parts of <math>E^{(1)}_{\rm elst}</math>) when calculated in the following ways:
- MOs calculated in reference geometry and rotated with molecule.
- Molecules rotated and MOs calculated in already rotated geometry.
These should be equivalent. And the MOs should be equivalent and related by a Wigner rotation matrix. This was not the case and I found small, but noticable differences that led to small differences in the e-n energies (there should also be differences in the e-e energies, but I still have to trace other errors here, so cannot be sure).
We should have had the following:
- Same e-n energies. But these were -4966220.470061 CM-1 and -4966223.294960 CM-1 for the two methods. The differences are small, but they should not be present. Also, they are small compared with the e-n energy (this was the electrons of the rotated water with the nuclei of the un-rotated partner) but there should be *no* difference! Also, the n-n energy was the same in both cases. So the geometries are identical to a very good precision.
- In this test, I had used only s-functions in the auxiliary basis. So