CCL: Question on NWChem run (UHF, singlet)
- From: Wirawan Purwanto <wirawan0-$-yahoo.com>
- Subject: CCL: Question on NWChem run (UHF, singlet)
- Date: Fri, 24 Mar 2006 13:52:46 -0800 (PST)
Sent to CCL by: Wirawan Purwanto [wirawan0[-]yahoo.com]
I am a new member of this list, and I appreciate the opportunity to
I have a question concerning running NWChem for UHF calculations for
singlet states. Let's take, for example, a water molecule (H2O) or a
singlet dimer (such as Li2, P2, etc.).
task scf energy
would simply give the RHF result, so let's not discuss that. I got some
suggestion to use
vectors swap alpha 4 5 swap beta 5 6
for a water molecule (STO-6G basis), but this does not get to the
lowest UHF energy. I have been trying swapping different states, it
would not yield any positive progress.
Prior to this, I used GAMESS, and I could run the singlet/UHF run
easily (I'm not for or against one package or the other, though). What
I did with GAMESS was to use the RHF final configurations as the
initial "alpha" states, and random configurations as the initial
states -- usually I'm lucky this way, and got the UHF total energy
lower than the RHF total energy.
Now, with NWChem, I could not find a way to fully "customize" the
initial configuration (i.e. specify the vector elements directly). The
only way I know is to use *.movecs file generated priorly. I don't have
time or energy to create my own *.movecs, though.
Does anyone has any suggestion? Or if you need more detail to answer my
question, I will gladly provide it.
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