Hi,
I've done ricc2 singlet state excitation energy calculations including the excited state properties for this molecule called daidzein, which is a member of isoflavones. I've done the same type of calculations using DFT too. The thing is with DFT I get for the lowest excited states, excitations such as HOMO to LUMO (from the 66th orbital to 67th), as expected. However, in ricc2 output I get for the lowest excitation, from the 61th orbital to 75th, and for the following excitations, from 66th to 78th, and such. On the other hand numerically, the excitation energies are consistent with I get with TDDFT. I am thus a bit confused about how to interpret the ricc2 output in terms of orbitals involving in excitations. Could you please help?
Thanks,
Maya