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Optimizing internal coordinates

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I'm trying to optimize an interaction between methyl sulfonate and a helium atom. I've input the cartesian coordinates of the sulfonate, a z-matrix for the helium, and used zcoor to (hopefully) keep the helium in the same orientation, so that it's only the interaction distance that I'm optimizing.

That said, it appears to run three mp3 calculations, each one giving the gradient along a different axis - is there any way of running it with internal coordinates? Just optimising along the He...O bond distance instead of along the helium position in x, y and z?

my input code is:

start h2o_freq
SCRATCH_DIR /mnt/beagle.tmp/jp.beagle/nwchemtemp/
memory total 3500 heap 500 stack 500 global 2500 mb
charge -1
geometry units angstroms
zcoord
angle 9 2 1 constant
torsion 9 2 1 5 constant
bond 9 2 constant
angle 10 2 9 constant
torsion 10 2 9 1 constant
end
zmatrix
S1 -0.04945627 0.15646615 -0.00020389
O1 1.33442349 0.69907524 -0.00102108
O2 -0.81156737 0.41859072 -1.24926153
O3 -0.81090550 0.42027917 1.24899274
C1 0.18326515 -1.63017590 0.00016201
H0 -0.79319973 -2.11765552 0.00142691
H1 0.74047742 -1.91840156 -0.89316346
H2 0.74136076 -1.91733246 0.89306828
Bq1 O1 1. S1 90. C1 0.0
He1 O1 2.1 Bq1 90. S1 180.0
zend
end

basis
* library 3-21g*
end

set geometry:actlist 10
driver
maxiter 100
end
title "N-acetyl taurine: 3-21g* RHF He interaction energy"
task scf optimize
basis
#basis is quite long so I've cut it out for the purposes of this post.
end
title "N-acetyl taurine : 6-311g(3d,3p) MP3 He interaction energy"
tce
io replicated
mp3
print low
end
task tce optimize

scf; rhf; print low; end
mp2; print low; end

  • Bert Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop
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TCE MP3 requires numerical gradients, which are done along the x,y, and z-coordinate system.
Bert

Quote: Oct 11th 3:34 pm
I'm trying to optimize an interaction between methyl sulfonate and a helium atom. I've input the cartesian coordinates of the sulfonate, a z-matrix for the helium, and used zcoor to (hopefully) keep the helium in the same orientation, so that it's only the interaction distance that I'm optimizing.

That said, it appears to run three mp3 calculations, each one giving the gradient along a different axis - is there any way of running it with internal coordinates? Just optimising along the He...O bond distance instead of along the helium position in x, y and z?

my input code is:

start h2o_freq
SCRATCH_DIR /mnt/beagle.tmp/jp.beagle/nwchemtemp/
memory total 3500 heap 500 stack 500 global 2500 mb
charge -1
geometry units angstroms
zcoord
angle 9 2 1 constant
torsion 9 2 1 5 constant
bond 9 2 constant
angle 10 2 9 constant
torsion 10 2 9 1 constant
end
zmatrix
S1 -0.04945627 0.15646615 -0.00020389
O1 1.33442349 0.69907524 -0.00102108
O2 -0.81156737 0.41859072 -1.24926153
O3 -0.81090550 0.42027917 1.24899274
C1 0.18326515 -1.63017590 0.00016201
H0 -0.79319973 -2.11765552 0.00142691
H1 0.74047742 -1.91840156 -0.89316346
H2 0.74136076 -1.91733246 0.89306828
Bq1 O1 1. S1 90. C1 0.0
He1 O1 2.1 Bq1 90. S1 180.0
zend
end

basis
* library 3-21g*
end

set geometry:actlist 10
driver
maxiter 100
end
title "N-acetyl taurine: 3-21g* RHF He interaction energy"
task scf optimize
basis
#basis is quite long so I've cut it out for the purposes of this post.
end
title "N-acetyl taurine : 6-311g(3d,3p) MP3 He interaction energy"
tce
io replicated
mp3
print low
end
task tce optimize

scf; rhf; print low; end
mp2; print low; end[/quote]


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