From chemistry-request@ccl.net Tue Mar 23 18:51:27 2004 Received: from mx5.net.nih.gov (mx5.net.nih.gov [165.112.130.36]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id i2NNpQjs007765 for ; Tue, 23 Mar 2004 18:51:27 -0500 Received: from mx5.net.nih.gov (localhost [127.0.0.1]) by mx5.net.nih.gov (8.12.10/8.12.8p1) with ESMTP id i2NNsG61030517 for ; Tue, 23 Mar 2004 18:54:16 -0500 Received: from pollux.cber.nih.gov (pollux.cber.nih.gov [128.231.52.5]) by mx5.net.nih.gov (8.12.10/8.12.8p1) with ESMTP id i2NNsGli030497; Tue, 23 Mar 2004 18:54:16 -0500 Date: Tue, 23 Mar 2004 18:31:33 -0500 From: Rick Venable To: Lubos Vrbka cc: chemistry.-at-.ccl.net Subject: Re: CCL:pressure scaling In-Reply-To: <406038AA.1040305.-at-.uochb.cas.cz> Message-ID: References: <406038AA.1040305.-at-.uochb.cas.cz> ReplyTo: Rick_Venable.-at-.nih.gov MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Spam-Status: No, hits=1.4 required=7.0 tests=LINES_OF_YELLING,RCVD_IN_NJABL, RCVD_IN_NJABL_RELAY autolearn=no version=2.61 X-Spam-Level: * X-Spam-Checker-Version: SpamAssassin 2.61 (1.212.2.1-2003-12-09-exp) on servernd.ccl.net On Tue, 23 Mar 2004, Lubos Vrbka wrote: > could someone explain to me how the isotropic and nonisotropic > pressure scaling in molecular dynamics work? > > can i make big mistake if i use isotropic scaling (nonisotropic is not > yet supported by pmemd) for non-isotropic system (solid-liquid > interface)? It is an issue for liquid:liquid interfaces; see COMPUTER-SIMULATION OF LIQUID/LIQUID INTERFACES. 1. THEORY AND APPLICATION TO OCTANE/WATER ZHANG YH, FELLER SE, BROOKS BR, PASTOR RW J CHEM PHYS 103 (23): 10252-10266 DEC 15 1995 See the discussions of NPAT and NPgammaT ensembles in the above reference. If there's a surface tension, it could be an issue for a solid:liquid interface as well, but it may depend on details of the solid phase model. =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+= Rick Venable 29/500 FDA/CBER/OVRR Biophysics Lab 1401 Rockville Pike HFM-419 Rockville, MD 20852-1448 U.S.A. (301) 496-1905 Rick_Venable.-at-.nih.gov ALT email: rvenable.-at-.speakeasy.org ------------------------------------- "Don't blame me, I voted for Kang." Homer =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=