From owner-chemistry- at -ccl.net Fri Sep 30 12:25:00 2011 From: "Andrea Ciccioli andrea.ciccioli###uniroma1.it" To: CCL Subject: CCL:G: Range of M.O.s used for correlation in CCSD calculations Message-Id: <-45560-110930122322-10288-bBFqthb2MY9C0SiJA2wraQ-.-server.ccl.net> X-Original-From: "Andrea Ciccioli" Date: Fri, 30 Sep 2011 12:23:18 -0400 Sent to CCL by: "Andrea Ciccioli" [andrea.ciccioli/./uniroma1.it] Hello everybody. I am doing CCSD(T) calculation with G03 on the Ca+ ion. In the output, the message "There is no correlation energy for this system" is given, and the HF energy is not corrected by the CC procedure. This is probably due to the criterium chosen to select the range of M.O.s used for correlation. Indeed, in the output the following message is reported: "Range of M.O.s used for correlation: 10 24". With this choice, I have seen that only 1 occupied MO is taken into account. My question is: how can I extend the range of MO used for correlation ? Thank you in advance Andrea Ciccioli Department of Chemistry Sapienza - Rome