From NWChem
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| 9:19:25 PM PDT - Sat, May 23rd 2015 |
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Quibble:
In ./src/vib/vib_wrtfreq.F,
truncated and rounded off constants are applied in
each loop iteration of the ZPE, thermal enthalpy and
energy calculation. The round-off error accumulation
reaches the milliHartree level for small molecules (e.g.,NH3)
is more than I'd like.
I suggest a modest correction.
According to NIST's CODATA 2011 docs
at http://physics.nist.gov/cuu/Constants/index.html ,
these constants are well-defined.
Speed of Light = 299792458 m/s = 2.99792458e+10 m/s
Planck's constant = 6.62606957e-34 J-sec = 6.62606957e-27 erg-sec
Boltzmann constant = 1.3806488e-23 J/K = 1.3806488e-16 erg-K
Ideal Gas Constant = 8.3144621 J/mol-K = 1.9872041 cal/mol-K
In the May 4 development version
Nwchem-dev.revision27039-src.2015-05-04/src/vib/vib_wrtfreq.F
lines 42,43 are:
parameter (c=2.998e+10,h=6.626e-27,kgas=1.3807e-16) ! cgs units
parameter (Rgas = 1.9863d0/1000.0d0/AUKCAL) ! atomic units
They may be revised to read:
parameter (c=2.99792458e+10,
& h=6.62606957e-27,
& kgas=1.3806488e-16) ! cgs units
parameter (Rgas = 1.9872041d0/1000.0d0/AUKCAL) ! atomic units
Thanks,
-drh
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Edited On 7:21:54 AM PDT - Sun, May 24th 2015 by Drhaney
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