From owner-chemistry _-at-_)ccl.net Tue Dec 10 18:18:00 2013 From: "Jens Spanget-Larsen spanget,+,ruc.dk" To: CCL Subject: CCL: SV: TDDFT (CAM-B3LYP) oscillator strength too high Message-Id: <-49418-131210175311-31733-sfdnNtxHobyD4rTIjrVxvw]_[server.ccl.net> X-Original-From: Jens Spanget-Larsen Content-Language: da-DK Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="us-ascii" Date: Tue, 10 Dec 2013 22:53:03 +0000 MIME-Version: 1.0 Sent to CCL by: Jens Spanget-Larsen [spanget[]ruc.dk] Dear Micaela, why do you think that an oscillator strength f = 2.7 is unphysical? This is certainly a large value, but it is not necessarily unreasonable. With TD-PBE1PBE/6-31+G*, we obtained f = 2.2 for the first optically allowed electronic transition in the D2d conformation of diphenyldiacetylene, see Thulstrup et al., PCCP 13, 16168-16174 (2011). Jens >--< ------------------------------------------------------ JENS SPANGET-LARSEN Office: +45 4674 2710 Dept. of Science (18.1) Fax: +45 4674 3011 Roskilde University Mobile: +45 2320 6246 P.O.Box 260 E-Mail: spanget[#]ruc.dk DK-4000 Roskilde, Denmark http://www.ruc.dk/~spanget ------------------------------------------------------ ________________________________________ Fra: owner-chemistry+spanget==ruc.dk[#]ccl.net [owner-chemistry+spanget==ruc.dk[#]ccl.net] på vegne af micaela matta micaela.matta2 .. unibo.it [owner-chemistry[#]ccl.net] Sendt: 10. december 2013 17:05 Til: Jens Spanget-Larsen Emne: CCL: TDDFT (CAM-B3LYP) oscillator strength too high Sent to CCL by: "micaela matta" [micaela.matta2 .. unibo.it] Dear CCL suscribers, I am running TD-DFT calculations on an organic molecule at level CAM-BLYP/6- 311G*. The first excited state has the correct energy compared to experimental results, but I obtained an unphysical f=2.7206!! How can I make sense of this result? Thanks Micaelahttp://www.ccl.net/cgi-bin/ccl/send_ccl_messagehttp://www.ccl.net/chemistry/sub_unsub.shtmlhttp://www.ccl.net/spammers.txt