Is the first excited state root obtained by NWCHEM IPCCSD the first IP?

[xiongyan21]

GAMESS can directly give IP. Is the first excited state root obtained by NWCHEM IPCCSD,e.g., F2 IPCCSD in QA tests, the first IP? Perhaps IE would be obtained based on this.

[xiongyan21]

I can verify the first excitation energy obtained is the first IP using NWCHEM because when I changed the keyword IPCCSD into CCSD in TCE, the obtained first excitation energy is much lower, i.e., 4.691836421578004eV, which is also significant larger than that using the multireference CI method in an article and those calculated by TDDFT or experimental data indexed in another one, thus the IP obtained by NWCHEM are unsuccessful for F2, and the first excitation energy is almost also.