From NWChem
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| 5:24:23 AM PST - Fri, Nov 16th 2012 |
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Hello all. Is there a simple way of performing a constrained minimization where one property (pair distance between two atoms, say) is held fixed and the rest of the degrees of freedom are relaxed? In Gaussian this is called a "bond length scan". I've been shown a way to do it in NWChem, but it's not nearly as concise as it seems like it should be.
Thanks for any help you can give,
Adam
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Huub Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop
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Forum Regular
Threads 1
Posts 185
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| 12:42:05 PM PST - Fri, Nov 16th 2012 |
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Hi Adam,
Yes there is. Below is an example of what you could call a "bond length scan". In this example a Cl- approaches CH3F in steps of 1 Angstrom. More details on the "zcoord" construct can be found at http://www.nwchem-sw.org/index.php/Release61:Geometry:
echo
title "cl-ch3f"
start cl-ch3f_dat
geometry units angstroms noautoz
Cl 0.0 0.0 -3.0
C 0.00000000 0.00000000 1.78977169
F 0.00000000 0.00000000 2.88489619
H -0.72912121 0.72912121 1.42221856
H -0.26687689 -0.99599810 1.42221856
H 0.99599810 0.26687689 1.42221856
end
charge -1
basis "ao basis" noprint
* library 6-31g*
end
dft
xc m06-2x
direct
end
driver
maxiter 100
end
geometry adjust
zcoord
bond 1 2 4.0 "r12" constant
end
end
task dft optimize
geometry adjust
zcoord
bond 1 2 3.0 "r12" constant
end
end
task dft optimize
geometry adjust
zcoord
bond 1 2 2.0 "r12" constant
end
end
task dft optimize
geometry adjust
zcoord
bond 1 2 1.0 "r12" constant
end
end
task dft optimize
Best wishes,
Huub
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