Hello all,

I’ve recently begun using Q-Chem EOM-EE-CCSD to to perform excited state geometry optimizations of open-shell diatomic clusters (eg CN-CO). Ideally I would like to use one z-matrix to sweep through Jacobi coordinates for the diatomics (r is the distance between the centers of mass between each pair, and theta being the angle created by CO and the C in CN). I thought I could put a dummy atom at the COM of the CO molecule, and another above the plane created by the CCO atoms (to keep all angles from approaching 180 degrees), but I have not had much luck with my DUMMY section. The below z-matrix (and other attempts) resulted in error messages stating I needed to list referenced centers in a dummy section. Do you have examples of z-matrices that would work better or examples of using the types of dummy atoms?

Thanks,

Benj

O

xx 1 xxo2

C 1 co3 2 coxx3

xx 2 xxxx4 3 xxxxc4 1 dih4

C 3 cc5 1 occ5 4 dih5

N 5 cn6 2 cnxx6 4 dih6

xxo2 0.550000

co3 1.100000

coxx3 1.000

xxxx4 1.000000

xxxxc4 90.000

dih4 179.000

cc5 2.000000

occ5 160.000

dih5 179.000

cn6 1.340000

cnxx6 60.000

dih6 0.000