From fox@fenris.ucsf.EDU Thu Feb 2 15:41:52 1995 Received: from cgl.ucsf.EDU for fox@fenris.ucsf.EDU by www.ccl.net (8.6.9/930601.1506) id PAA17996; Thu, 2 Feb 1995 15:13:08 -0500 Received: from fenris.ucsf.EDU (fenris.ucsf.EDU [128.218.14.26]) by cgl.ucsf.EDU (8.6.7/GSC4.24) with SMTP id MAA26679 for ; Thu, 2 Feb 1995 12:13:05 -0800 Received: by fenris.ucsf.EDU (1.38.193.4/GSC4.21) id AA16001; Thu, 2 Feb 1995 12:13:03 -0800 From: fox@fenris.ucsf.EDU (Thomas Fox) Message-Id: <9502022013.AA16001@fenris.ucsf.EDU> Subject: G92-DFT bug? H and LYP To: CHEMISTRY@ccl.net Date: Thu, 2 Feb 95 12:13:03 "PST Mailer: Elm [revision: 70.85] Dear CCLers, I was using the DFT module of Gaussian 92 (HP-PARisc-HPUX-G92/DFT-RevF.4) and came across something that looks like a bug to me: when I try to calculate an one-electron system (like the H atom) and use the Lee-Yang-Parr functional, my G92 version stops with an IEEE division by zero error. I browsed through the code, and sure enough found in the LYP subroutine a division by Rho(Beta), which is, in the case of one electron, equal zero. I dont have access to the original paper right now, so could someone just reassure me that this behavior is definitely an unexpected one, and that it doesnt mean that the LYP functional is not valid in the limit of one electron or if I only have electrons of one spin species (Gaussian shouldnt abort that ungracefully, anyway...). A related question is how to get in contact with these Gaussian guys...I sent a message to help@gaussian.com some weeks ago, but havent heard from them back. And, could anybody who has access to a DFT implementation (maybe there is even a G92 version out there that doesnt show this behavior) that supports Becke 3 parameter XC in connection with the LYP C functional calculate the energy for a H radical (with a 6-31G* basis) for me? Pointers to papers where this has been done (maybe as a test case for the functional) are, of course, also highly welcome. Thanks a lot, Thomas -- Thomas Fox e-mail: fox@cgl.ucsf.edu Dept. of Pharmaceutical Chemistry University of California San Francisco, CA 94143-0446 ,,, (o o) -----------------------------ooo-(^)-ooo------------------------------------- U The years of peak mental activity are undoubtedly between the ages of four and eighteen. At four we know all the questions, at eighteen all the answers. ----------------------------------------------------------------------------- $$$ Disclaimer: opinions blah blah blah mine... $$$ ***