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HC4N |
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in Carbene |
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The molecular structure of carbene HC4N
was optimized at the CCSD/DZP, CCSD(T)/DZP, CCSD/TZ2P and CCSD(T)/cc-pVTZ
levels of theory by McCarthy et al. [1]. Calculation of the nitrogen
nqcc's was made here on the latter two structures. The results are
compared in Tables 1 and 2 with the experimental nqcc's [1]. Structure
parameters are compared in Table 3. |
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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 nqcc's (percentage of
average experimental nqcc). RSD is the residual stand deviation
of calibration of the model for calculation of
the nqcc's. |
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Table 1. Nitrogen nqcc's
in HC4N (MHz). Calculation was made
on the CCSD(T)/cc-pVTZ structure of McCarthy et al. [1]. |
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Calc. |
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Expt. [1] |
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14N |
Xaa |
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3.410 |
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3.279 |
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Xbb |
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0.321 |
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0.490 * |
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Xcc |
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3.088 |
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2.790 * |
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|Xab| |
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2.479 |
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RMS |
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0.211 (9.7 %) |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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1.558 |
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Xyy |
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3.088 |
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Xzz |
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4.646 |
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ETA |
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0.329 |
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Øz,a |
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26.52 |
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Øa,CN |
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25.93 |
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Øz,CN |
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0.58 |
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*
Calculated here from Xaa and Xbb - Xcc =
-2.300(5) MHz [1]. |
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Table 2. Nitrogen nqcc's
in HC4N (MHz). Calculation was made
on the CCSD/TZ2P structure of McCarthy et al. [1]. |
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Calc. |
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Expt. [1] |
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14N |
Xaa |
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3.425 |
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3.279 |
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Xbb |
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0.354 |
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0.490 * |
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Xcc |
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3.071 |
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2.790 * |
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|Xab| |
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2.543 |
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RMS |
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0.199 (9.1 %) |
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RSD |
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0.030 (1.3 %) |
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Xxx |
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1.632 |
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Xyy |
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3.071 |
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Xzz |
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4.703 |
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ETA |
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0.306 |
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Øz,a |
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26.69 |
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Øa,CN |
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25.95 |
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Øz,CN |
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0.74 |
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*
Calculated here from Xaa and Xbb - Xcc =
-2.300(5) MHz [1]. |
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| Table 3. Structure parameters (Å and degrees). CCSD(T)/cc-pVTZ and CCSD/TZ2P [1]. |
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CCSD(T) |
CCSD |
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HC(1) |
1.081 |
1.082 |
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C(1)C(2) |
1.331 |
1.327 |
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C(2)C(3) |
1.292 |
1.292 |
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C(3)C(4) |
1.427 |
1.439 |
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C(4)N |
1.162 |
1.155 |
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HC(1)C(2) |
121.1 |
121.3 |
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HC(1)C(4) |
116.0 |
116.2 |
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C(1)C(2)C(3) |
178.0 |
178.0 |
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C(1)C(4)N |
178.2 |
178.0 |
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[1] M.C.McCarthy, A.J.Apponi, V.D.Gordon, C.A.Gottlieb,
P.Thaddeus, T.D.Crawford, and J.F.Stanton, J.Chem.Phys. 111,6750(1999). |
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Table of Contents |
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Molecules/Nitrogen |
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HC4N.html |
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Last
Modified 24 Nov 2003 |
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