From chemistry-request@ccl.net Sun Apr 17 18:39:09 2005 Received: from server.ccl.net (ccl [127.0.0.1]) by server.ccl.net (8.13.1/8.13.1) with ESMTP id j3HMd9xg031706 for ; Sun, 17 Apr 2005 18:39:09 -0400 Received: (from apache@localhost) by server.ccl.net (8.13.1/8.13.1/Submit) id j3HMd9ut031705 for chemistry () ccl.net; Sun, 17 Apr 2005 18:39:09 -0400 Date: Sun, 17 Apr 2005 18:39:09 -0400 Message-Id: <200504172239.j3HMd9ut031705 () server.ccl.net> X-Authentication-Warning: server.ccl.net: apache set sender to chemistry-request () ccl.net using -f From: "Bryan, , Wong" To: chemistry () ccl.net X-Web-Message-Number: 050417183826-31685 Subject: W:two electron integrals X-Spam-Status: No, score=-2.3 required=5.0 tests=ALL_TRUSTED, FROM_ENDS_IN_NUMS autolearn=failed version=3.0.1 X-Spam-Checker-Version: SpamAssassin 3.0.1 (2004-10-22) on server.ccl.net Hi, I am trying to calculate the 2-electron integrals (the electron repulsion integrals) in Gaussian. I have used the following keywords on my diatomic molecule hf (as a test case). p ExtraLinks=L316 NoRaff Symm=NoInt SCF=Conventional Pop=Full IOP(3/33=6) 3-21G HF test case 0 1 1 0.000000 0.000000 -1.152873 9 0.000000 0.000000 0.432327 With this 3-21G test case, it generates 11 basis functions. At the end of the output, I get 677 two-electron integrals labelled by i, j, k, and l. I'm just a little confused about the output: (1) Are these integrals calculated for the 11 molecular orbitals or for the 11 basis set? (2) Shouldn't I get 2211 outputted integrals instead of 677? (2211 is the number of unique combinations of i, j, k, and l taking into account the symmetry of the integrand). Any help is greatly appreciated! Thank you, Bryan