From owner-chemistry@ccl.net Fri Oct 12 10:16:00 2012
From: "Supriya Shrestha sshrestha[*]fas.harvard.edu" <owner-chemistry++server.ccl.net>
To: CCL
Subject: CCL: EOM-CCSD-EA calculation in Qchem
Message-Id: <-47757-121012101159-16680-v+EhYrnItyNRa4bBgdWFlg++server.ccl.net>
X-Original-From: "Supriya  Shrestha" <sshrestha!=!fas.harvard.edu>
Date: Fri, 12 Oct 2012 10:11:57 -0400


Sent to CCL by: "Supriya  Shrestha" [sshrestha(_)fas.harvard.edu]
Hello all,

I want to do some EOM-CCSD-EA calculations in Qchem but before I do that in order to make sure that I am running the calculations correctly I am benchmarking it using a paper by Nooijen and Bartlett (J. Chem. Phys. 102, 3629 (1995); http://dx.doi.org/10.1063/1.468592 ). Below is the link to the paper:

http://jcp.aip.org/resource/1/jcpsa6/v102/i9/p3629_s1

I am unable to replicate the results and the values are all over the place. Here are a couple of results I got with the def2-SVPD set and 6-31+G* set. The paper uses different basis sets for different molecules but for all molecules I used the same basis set. Also all EOM calculations were carried out with neutral geometry.

def-2-SVPD:

BeH Excitation energy = -1.7848 eV.
BH Excitation energy = 0.4104 eV.
BO Excitation energy = -2.2083 eV.
CN Excitation energy = -3.3531 eV.
MgH Excitation energy = -1.8074 eV

6-31+G*

BeH Excitation energy = -0.1383 eV.
BH Excitation energy = 0.2588 eV.
BO Excitation energy = -2.1315 eV.
CN Excitation energy = -3.3969 eV.
MgH Excitation energy = -0.4930 eV

Bartlett paper values in eV for neutral:

BeH 0.48
BO 2.31
CN 3.63
MgH 0.65

Below is a sample of an input file I am using:

$molecule
0 2
Be -1.0862574577414126 3.7870390811715033 0.0000000000000000
H 0.2612574577414080 3.8579609188284949 0.0000000000000000
$end

$rem
MEM_STATIC 300
MEM_TOTAL 3500
JOBTYPE SP
BASIS 6-31+G*
CORRELATION CCSD
SYM_TOL 1
CC_SYMMETRY FALSE
EOM_EA_STATES [1]
PURECART 1111
$end


The reason that I am not using symmetry is that I want to be able to use this for a large set of molecules and in that case getting the irreducible representations/point group will be a chore.

Thanks for your help in advance!