Sent to CCL by: Susi Lehtola [susi.lehtola[a]alumni.helsinki.fi]On 03/24/2015 06:39 AM, Víctor Luaña Cabal victor ~~ fluor.quimica.uniovi.es wrote:
Sent to CCL by: =?iso-8859-1?Q?V=EDctor_Lua=F1a?= Cabal [victor^fluor.quimica.uniovi.es] On Tue, Mar 24, 2015 at 05:44:52AM -0400, Ahmad Ziaee ahmad.ziaee*ul.ie wrote:Sent to CCL by: "Ahmad Ziaee" [ahmad.ziaee%%ul.ie] Hi All,Ahmad, 1) Your system is VERY large. I advise you to start an approach in steps. First, try to optimize the geometry using a cheap and sure nethod like HF/3-21G. Then start a proccess of using the feometry from a level to start the calculation of un upper level of theory and basis sets. If the number of electrons in your system is even you can start at the HF = RHF level. If it is odd you could start from UHF.
Since this is a PBC calculation, HF is *not* cheap: the long range exchange kills you. DFT will be much cheaper, and you might also want to consider using density fitting. If you need the accuracy of hybrid functionals, try using a short-range hybrid like HSE.
My guess is that the problem are the force constants, since the system isn't that big and the basis set is very small. If you drop the calcfc argument, it should run.
-- ----------------------------------------------------------------------- Mr. Susi Lehtola, PhD Chemist Postdoctoral Fellow susi.lehtola^-^alumni.helsinki.fi Lawrence Berkeley National Laboratory http://www.helsinki.fi/~jzlehtol USA -----------------------------------------------------------------------