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Oxygen
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Introduction
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In
the Tables that follow, RSD is the residual standard deviation of the
linear regression analysis of the calculated efg's versus the
experimental nqcc's for the molecules given on the previous
page.
This may be taken as an estimate of the
uncertainty
in the calculated nqcc's. (Note: A RSD of 0.043 MHz is 1.5 %
of
the
average absolute experimental nqcc for the molecules used for
calibration.) All three diagonal components of the efg
tensors
are plotted against the corresponding components of the experimental
nqcc tensors. This assures, because the tensors are traceless, that the
linear regression line pass through the origin. The slope of
this
line is eQeff/h from which the value
of Qeff is extracted. Qeff
is the model
dependent nuclear electric quadrupole moment effective
for calculation of the nqcc's. For comparison, the currently
recommended Q for 17O
is -25.58(22) mb.
It is our goal to reproduce accurately as well as efficiently
the
experimental nqcc's - not Q. It is sufficient - indeed, all that can be
expected at the level of theory in this work - that Qeff
and
Q agree to within a few percent. |
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For
the Dunning correlation consistent basis sets, G03 and EMSL indicate
the source of the bases used for the calculation. G03 is
Gaussian
03, which contains these bases somewhat modified to increase
computational efficiency. EMSL is the online EMSL Basis Set
Library. cc-pCVTZ/cc-pVTZ is cc-pVTZ with extra functions -
on
only the oxygen atom - that are designed for core-valence correlation. |
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Polarization
and diffuse functions used with the Alhrichs TZV bases are those
developed for use with the Pople type bases. The
6-311++G(3df,3p)
and
TZV++(3df,3p)) bases, for example, contain the same polarization and
diffuse functions -
same exponents and coefficients. |
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Alhrichs' QZVP bases are available at http://www.ipc.uni-karlsruhe.de/tch/tch1/index.de.html. |
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With
the MP2 and MP3 methods, FC = frozen core, and FULL = all electron
correlation.
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Results
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Table
1. Calibration of
HF-DFT/6-311++G(3df,3p). RSD (MHz) and
Qeff (mb). |
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Method
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RSD
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-Qeff
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B1B95
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0.039
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24.75(5)
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B1LYP
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0.041
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24.70(5)
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B3LYP
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0.044
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24.84(6)
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B3P86
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0.067
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25.08(9)
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B3PW91
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0.079
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25.08(11)
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mPW1PW91
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0.081
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24.99(11)
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PBE1PBE
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0.079
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25.15(11)
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B98
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0.119
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25.05(16)
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B971
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0.093
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25.14(13)
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B972
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0.182
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25.10(25)
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Table
2. Calibration of B1B95/Basis. RSD (MHz) and
Qeff (mb). |
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B1B95/Basis
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RSD
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-Qeff
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6-311G(3df,3p)
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0.050
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24.36(6)
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6-311+G(3df,3p)
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0.039
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24.75(5)
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6-311++G(3df,3p)
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0.039
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24.75(5)
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TZV(3df,3p) |
0.045
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24.64(6)
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TZV+(3df,3p) |
0.051
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24.81(7)
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TZV++(3df,3p)
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0.051
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24.80(7)
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QZVP |
0.059 |
24.37(8) |
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cc-pVTZ (G03)
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0.052
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24.41(7)
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aug-cc-pVTZ
(G03)
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0.041
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24.83(6)
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aug-cc-pVTZ
(EMSL)
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0.041
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24.83(6)
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aug-cc-pCVTZ/aug-cc-pVTZ
(EMSL) *
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----
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----
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*
G03 error message, OCSe: "Convergence failure -- run terminated."
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Table
3. Calibration of B1LYP/Basis. RSD (MHz) and
Qeff (mb). |
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B1LYP/Basis
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RSD
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-Qeff
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6-311+G(3df,3p)
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0.041
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24.69(6)
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6-311++G(3df,3p)
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0.041
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24.70(5)
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TZV(3df,3p) |
0.056
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24.61(8)
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TZV++(3df,3p)
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0.066
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24.81(9)
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QZVP |
0.080 |
24.32(10) |
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aug-cc-pVTZ
(G03)
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0.056
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24.82(7)
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aug-cc-pCVTZ/aug-cc-pVTZ
(EMSL)
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0.048
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24.94(6)
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Table
4. Calibration of B3LYP/Basis. RSD (MHz) and
Qeff (mb). |
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B3LYP/Basis
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RSD
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-Qeff
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6-311+G(3df,3p)
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0.045
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24.84(6)
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6-311++G(3df,3p)
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0.044
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24.84(6)
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TZV(3df,3p) |
0.064
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24.77(8)
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QZVP |
0.085 |
24.46(11) |
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aug-cc-pVTZ
(G03)
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0.061
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24.97(8)
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aug-cc-pCVTZ/aug-cc-pVTZ
(EMSL)
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0.054
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25.07(7)
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Table
5. Calibration of Ab
initio Method/Basis. RSD (MHz) and
Qeff (mb). |
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Method/6-311++G(3df,3p)
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RSD
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-Qeff
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HF
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0.140
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23.73(18)
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MP2(FC)
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0.200
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26.56(28)
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MP2(FULL)
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0.191
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26.48(27)
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MP3(FC)
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0.097
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24.58(13)
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MP3(FULL)
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0.101
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24.52(13)
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MP4(SDQ)
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0.027
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25.50(4)
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MP4(SDQ)/6-311++G(3df,3pd)
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0.022
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25.45(3)
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Method/TZV(3df,3p)
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HF
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0.140
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23.46(18)
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MP2(FULL)
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0.190
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26.34(27)
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MP3(FULL)
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0.085
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24.36(11)
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MP4(SDQ)
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0.032
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25.25(4)
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Go back
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Table
of Contents
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Oxygen Molecules
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