From chemistry-request@server.ccl.net Mon Feb 28 15:03:02 2000 Received: from mailoff.mtu.edu (campus1.mtu.edu [141.219.69.101]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id PAA20198 for ; Mon, 28 Feb 2000 15:03:01 -0500 Received: from mail.mtu.edu (campus0.mtu.edu [141.219.69.100]) by mailoff.mtu.edu (8.9.3/8.9.3) with ESMTP id PAA01522 for ; Mon, 28 Feb 2000 15:02:44 -0500 (EST) Received: from abyss1.cee.mtu.edu (abyss1.cee.mtu.edu [141.219.57.61]) by mail.mtu.edu (8.9.3/8.9.3) with ESMTP id PAA24864 for ; Mon, 28 Feb 2000 15:02:42 -0500 (EST) Received: from cepc17 (cepc17.cee.mtu.edu [141.219.58.71]) by abyss1.cee.mtu.edu (8.8.8/8.8.8/mturelay-1.2) with SMTP id PAA18776 for ; Mon, 28 Feb 2000 15:02:42 -0500 (EST) X-Authentication-Warning: abyss1.cee.mtu.edu: Host cepc17.cee.mtu.edu [141.219.58.71] claimed to be cepc17 Message-Id: <3.0.6.32.20000228150248.00943630@pop.cee.mtu.edu> X-Sender: ssanongr@pop.cee.mtu.edu X-Mailer: QUALCOMM Windows Eudora Light Version 3.0.6 (32) Date: Mon, 28 Feb 2000 15:02:48 -0500 To: chemistry@ccl.net From: Sompop Sanongraj Subject: Need some helps for adsorption energy Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Hi all I try to apply the computational calculation for adsorption field. First, I try to calculate adsorption interaction (at zero coverage) between noble gases (He, Ne, Ar and Kr) and the graphite lattice (7 rings) as shown in Figure below. ____ / \ ____/ \____ / \ / \ / \____/ \ \ / \ / \____/ o \____/ / \ / \ / \____/ \ \ / \ / \____/ \____/ \ / \____/ Where (o) in the center denotes the atom of noble gas above the ring cluster representing the graphite. To do this, I optimized and calculated the energy of the graphite lattice(E1), each noble gas (E2) and the merged system between graphite lattice and each noble gas (E3). For each step, the methods and basis sets are the same for calculating E1, E2 and E3. Then I simply calculated the adsorption interaction energy by E3-(E1+E2). The optimization methods basis sets (I used gaussian 98, A.7) and the results are shown below. Adsorption Interaction Energy (E3-(E1+E2)), cal/mole Methods and basis sets He Ne Ar Kr RHF/6-311g(d) -2.07078 -19.39004 -17.06826 -13.93071 RHF/6-311g(d)//B3LYP/6-311g(d) -308.92293 -17.50751 234.50030 793.98777 B3LYP/STO-3g -4.64357 -2.51004 112.95171 48.82024 B3LYP/6-311g(d,p) -22.40209 -570.34338 -22.08833 -44.11392 For the expected result, we should obtain the linear relationship between the adsorption energy and the atomic no. of noble gas because the dispersion interaction is dominant (theorrtically, the dispersion interaction depends on polarizability). Also the sign of adsorption interaction should be negative because it supposes to be released energy. I got no luck. As you can see from my results, there are no methods and basis sets that the results will follow the expected result. Can anybody give me some suggestion about the method or basis set that I used or anything that I should aware of when I do this kind of calculation? Thanks in advance dom Sompop Sanongraj 208 Church Street Hancock MI 49930. TEL: (906) 482 9377