From owner-chemistry@ccl.net Thu Mar 23 10:27:00 2017 From: "Bertram Jaeger bertram.jaeger(0)physik.tu-berlin.de" To: CCL Subject: CCL:G: Becke Johnson correction on vibrational mode intensities, e.g. Si6 Message-Id: <-52715-170323095601-9084-v/NhoYU2a8EIXk12hwXZvA_._server.ccl.net> X-Original-From: "Bertram Jaeger" Date: Thu, 23 Mar 2017 09:55:59 -0400 Sent to CCL by: "Bertram Jaeger" [bertram.jaeger],[physik.tu-berlin.de] I encoutered a dramatic change of IR mode intensity using the empiricaldispersion correction gd3bj in gaussian09 for Si6. To be more specific, Si6 cation (doublet) is DFT calculated with cam-b3lyp and the aug-cc-pVQZ basis set. I added empiricaldispersion=gd3 to include dispersion forces. But including the becke johnson dumping using the keyword "empiricaldispersion=gd3bj), the highes vibrational mode (breathing mode) gets intensified from almost zero to a comparable intensity like one of the others most intense modes. Problem is, that this "new" mode isnt observed in the vibrational spectrum (e.g. from Lyon et al, J. AM. CHEM. SOC., 2009, 131 1115-1121). Reading the Grimme paper (Grimme et al, J Comput Chem 32: 1456-1465, 2011) I understand that the gd3bj includes a dispersion correction at small distances, which goes to zero for the gd3. Maybe for the Si6+ cluster, the distances are in this "small distance" regime, so another force will be effective. In the end, I cant explaine why there is such an effect of energy correction on a vibrational mode intensity. Does someone know more about it, or can help me understand this effect? Is the Becke Johnson dumping even applicable on Silicon cluster, since they probably have strong covalent bonds? I can provide pictures of the spectra, geometry, mode vectors and input files for gaussian09. I am an experimental physicist, so please excuse if Im not using the proper nomenclature or any compliant formulation. all the best Bertram Jaeger From owner-chemistry@ccl.net Thu Mar 23 11:36:00 2017 From: "Arun K. Pal arunpal__buffalo.edu" To: CCL Subject: CCL:G: How can I convert Debye-ang**3 to atomic unit? Message-Id: <-52716-170323111920-8272-/UGctulQn66/ppCb8S6C+Q|server.ccl.net> X-Original-From: "Arun K. Pal" Date: Thu, 23 Mar 2017 11:19:18 -0400 Sent to CCL by: "Arun K. Pal" [arunpal/./buffalo.edu] Dear all, I wanted to calculate the longitudinal (z-axis) static polarizability and hyperpolarizabilities beta and gamma of polybutatriene oligomers by using Gaussian09. I have used [#P CCSD=(T,maxcyc=200)/gen gfinput polar scf=(conver=4) pop=reg (basis sets: for C, aug-cc-pvdz and for H, cc-pvdz)] in the command line, is it right for CCSD(T) calculations? By using the above command line the output gives Quadrupole, octapole and hexadecapole moments in Debye-ang , Debye-ang**2 and Debye-ang**3, respectively. How do I convert them to atomic unit? With best regards, Arun K Pal Department of Chemistry SUNY, Buffalo, USA