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CH2I-CH2F
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Iodine
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Nuclear
Quadrupole Coupling Constants |
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in gauche 1-Iodo-2-Fluoroethane |
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Calculation of the
iodine nqcc's in gauche
1-iodo-2-fluoroethane was
made on a molecular structure obtained by MP2/6-311G(3df,3pd)
optimization, and on this structure but with empirically
corrected C-C, CF, and CH bond lengths (approximate re). These calculated nqcc's are compared with
the experimental values of Niide and Ohkoshi [1] in Table 1. Structure
parameters are given in Table 2,
rotational constants in Table 3. |
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In Table 1, subscripts a,b,c refer to the principal axes of the inertia
tensor, subscripts x,y,z to the principal axes of the nqcc tensor.
The nqcc y-axis is chosen coincident with the inertia c-axis, these
are perpendicular to the plane of the molecule. Ø (degrees)
is the angle between its subscripted parameters. ETA = (Xxx
- Xyy)/Xzz. |
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RMS is the root mean square
difference between calculated and experimental diagonal nqcc's (percent of the
average of the magnitudes of the experimental nqcc's). RSD is the residual standard deviation
of calibration of the B1LYP/6-311G(df,p) model for calculation of
the nqcc's. |
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Table
1. 127I nqcc's in g-CH2I-CH2F
(MHz). |
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Calculation was made on the following structures: |
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ropt (1) = MP2/6-311G(3df,3pd) optimization, and |
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ropt (2) = MP2/6-311G(3df,3pd) optimization with empirically corrected C-C, CF, and CH bond lengths. |
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Calc. (1)
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Calc. (2) |
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Expt. [1] |
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Xaa |
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1048.0 |
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1048.2 |
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1043.69(87) |
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Xbb |
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185.9 |
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186.2 |
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183.72(48) |
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Xcc |
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862.2 |
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862.0 |
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859.97(99) |
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|Xab| |
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1264.1 * |
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1264.5 * |
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1250.9(12) * |
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|Xac| |
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355.3 |
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356.1 |
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384.0(14) |
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|Xbc| |
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248.5 |
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248.9 |
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288.1(44) |
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RMS |
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3.1 (0.44 %) |
3.2 (0.46 %) |
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RSD |
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15.2 (1.23 %) |
15.2 (1.23 %) |
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Xxx |
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920.9 |
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921.1 |
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910.9 |
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Xyy |
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984.6 |
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985.0 |
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995.1 |
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Xzz |
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1905.4 |
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1906.1 |
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1906.0 |
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ETA |
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0.0334 |
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0.0336 |
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0.04417 |
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Øz,CI |
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0.63 |
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0.63 |
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* The algebraic sign of the product XabXacXbc is negative. |
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| Table 2. g-CH2I-CH2F. Heavy atom structure parameters
(Å and degrees). Complete structures are given here in Z-matrix format. |
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| ropt(1) = MP2/6-311G(3df,3pd) optimization. |
| ropt(2) = MP2/6-311G(3df,3pd)
optimization with MP2/6-311+G(d,p) corrected C-C and CF bond lengths,
and MP2/6-31G(d,p) corrected CH bond lengths (see here). |
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ropt(1) |
ropt(2) |
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CI |
2.1289 |
2.1289 |
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C-C |
1.5060 |
1.5043 |
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CF |
1.3765 |
1.3784 |
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ICC |
112.06 |
112.06 |
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CCF |
110.18 |
110.18 |
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FCCI |
- 63.77 |
- 63.77 |
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| Table 3. g-CH2I-CH2F. Rotational Constants (MHz). |
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ropt(1) |
ropt(2) |
Expt. [1] |
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A |
11 860.4 |
11 843.0 |
11 828.802(25) |
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B |
1 779.1 |
1 780.1 |
1 740.2663(76) |
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C |
1 620.8 |
1 621.4 |
1 588.7756(75) |
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[1] Y.Niide and I.Ohkoshi, J.Mol.Spectrosc. 140,301(1990). |
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CH3CH2I |
CH3I |
CH3-CHI-CH3 |
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Table of Contents |
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Molecules/Iodine |
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gCH2ICH2F.html |
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Last
Modified 10 Dec 2008 |
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