Dear CP2K community, I would like to calculate the Vertical Ionization Potential (VIE) of several species, both in the gas phase and in solution. As an initial benchmark, I attempted to compute the VIE of OH⁻ in the gas phase. Its experimental value has been reported as 42.2 kcal/mol (1.83 eV), and similar values have been obtained from SCS-MP2 calculations. (https://pubs.acs.org/doi/10.1021/acs.jpclett.2c01721)I would like to repeat this calculation at the GW level because, to my understanding (please correct me if I am mistaken), the relation −E_{HOMO} ~ VIE is expected to be particularly accurate at GW level. I have seen a study study performing such calculations at the G₀W₀ level for OH-, although not using CP2K. (<a href="https://doi.org/10.1063/1.4887259" target="_blank" style="color: rgb(149, 79, 114); text-decoration: underline;">https://doi.org/10.1063/1.4887259</a>)I am attaching my input file. I took inspiration from the CP2K GW tutorial (<a href="https://www.cp2k.org/exercises:2017_uzh_cp2k-tutorial:gw" style="color: rgb(149, 79, 114); text-decoration: underline;">https://www.cp2k.org/exercises:2017_uzh_cp2k-tutorial:gw</a>). The OH⁻ structure was previously optimized at the PBE-D3/TZV2P-MOLOPT level, and also at the DC-R2SCAN/TZV2P level.I tested three GW flavours (evGW, G₀W₀, and evGW₀). The closest agreement was obtained with evGW, which gives −E_{HOMO} ≈ VIE ≈ 0.8 eV, still significantly (1 eV smaller) from the reference gas-phase value (1.83 eV). Am I missing something in my setup? Any suggestions or recommendations (even of alternative approaches) are welcome.Thank you very much for your time and help. Best, Ivan. -- You received this message because you are subscribed to the Google Groups "cp2k" group. To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k+unsubscribe@googlegroups.com">cp2k+unsubscribe@googlegroups.com</a>. To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/f094d125-afdb-433e-8c25-047bc0c90db2n%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/f094d125-afdb-433e-8c25-047bc0c90db2n%40googlegroups.com</a>.