I'm trying to calculate paramagnetic NMR shielding constants using NWChem on a small inorganic anion containing 25 atoms. Using smaller basis sets, the calculation is slow but manageable. I wanted to use a larger basis set, so I have switched to Def2-TZVP with the following input file:
echo
start nmrepr
title "Paramagnetic NMR/EPR Calculation"
memory 1500 mb
charge -3
geometry noautoz units angstrom nocenter
symmetry c1
load geom.xyz
end
basis "aobasis" print
* library Def2-TZVP
end
relativistic
zora on
zora:cutoff_NMR 1d-8
zora:cutoff 1d-30
end
dft
odft
mult 3
xc pbe0
iterations 100
convergence lshift 0.75 rabuck 30
end
property
gshift
hyperfine
shielding
end
task dft property
For the sake of comparison, I'd like to get the numbers from this calculation before adding diffuse functions. Unfortunately, NWChem is making *enormous* files on my hard drive and crashing my computer. Before even getting to SCF convergence, I get an error:
eaf_write: rc ne bytes -1999 bytes 524288
IO offset 13682343936.000000
IO error message >Write failed 0
Checking my hard drive, NWChem has created eight nmrepr.aoints.* files (one for each processor) that are each 14 GB in size. Is there some way to avoid this? I should hope that 25 atoms is not too many to use a triple-zeta basis set.
If I leave out the relativistic block, the calculation runs with no problems. However, I can't get g or hyperfine tensors without ZORA.
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