From owner-chemistry@ccl.net Thu Oct 28 04:05:00 2010 From: "Lars Goerigk lars.goerigk#,#uni-muenster.de" To: CCL Subject: CCL:G: Double hybrid functionals for excited states with Gaussian09 Message-Id: <-43025-101028040035-16019-/vR4robuXdGjEygBcI0W0Q^^server.ccl.net> X-Original-From: Lars Goerigk Content-Transfer-Encoding: 7bit Content-Type: Text/Plain; charset="iso-8859-15" Date: Thu, 28 Oct 2010 10:00:27 +0200 MIME-Version: 1.0 Sent to CCL by: Lars Goerigk [lars.goerigk _ uni-muenster.de] TD-B2PLYP works as follows: First, you perform a ground state B2LYP calculation. The perturbative correction is not needed if you are not interested in any ground state properties, because you are just interested in the resulting KS-orbitals. Then a standard TD-DFT treatment (i.e. TD-B2LYP) is carried out, which gives you excitation energies and transition moments of TD-BHLYP quality. The B2LYP orbitals and TD-B2LYP excitation energies and amplitudes are then used for a CIS(D) type treatment to correct the TD-B2LYP energies. I do not know if such a treatment is possible in Gaussian by adjusting some IOPs. I assume that the CIS(D) routine will crash if TD-DFT results are used as an input. However, the routine may not fail with an CIS like input. The Tamm-Dancoff- Approximation is basically CIS. I do not know if Gaussian does TDA-DFT. Basically you can then carry out the CIS(D) correction based on your TDA-B2LYP result. This gives you TDA-B2PLYP energies. This was also discussed in the 2007 Grimme/Neese paper. TDA-DFT usually gives you very similar energies to TD-DFT. But again, I do not know whether Gaussian can handle this with IOPs, but it's worth testing it. Maybe the Gaussian people can help you with the IOPs if you contact them; maybe it's even possible to do full TD-B2PLYP. Another option would be ORCA, which is freely available. It does TDA-B2PLYP, but not full TD-B2PLYP. I hope these information are somehow useful for you. Cheers, Lars On Wednesday 27 October 2010 05:08:27 pm you wrote: > Sent to CCL by: "Lara Martinez Fernandez" [lara.martinez*o*uam.es] > I am trying to run some TD-DFT calculation (for excited states) using > double hybrid functionals with Gaussian09. I have some doubts about how > TD-B2PLYP,TD-B2GP-PLYP work. If I dont misunderstood, first I have to run > a B2LYP calculation for the ground state and then use this orbitals and > amplitudes to run the CIS(D) correction for the rest of excited states. I > dont know if this procedure is possible with Gaussian09. Do anyone know > how to do that? I guess there must be any keyword to read the B2LYP (of > the ground state) orbitals and not optimise them in the CIS(D) > calculation. > > > Thanks in advance, Lara>