HC4N




 








Nitrogen


Nuclear Quadrupole Coupling Constants


in Carbene


 







 
 
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.
 
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.
 
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.
 
 
   







Table 1.  Nitrogen nqcc's in HC4N (MHz).  Calculation was made on the CCSD(T)/cc-pVTZ structure of McCarthy et al. [1].
   










Calc.
Expt. [1]
   






14N Xaa - 3.410 - 3.279
Xbb 0.321 0.490 *
Xcc 3.088 2.790 *
|Xab| 2.479
 
RMS 0.211 (9.7 %)
RSD 0.030 (1.3 %)
 
Xxx 1.558
Xyy 3.088
Xzz - 4.646
ETA 0.329
Øz,a 26.52
Øa,CN 25.93
Øz,CN   0.58
 
   
* Calculated here from Xaa and Xbb - Xcc = -2.300(5) MHz [1].
 
 
   







Table 2.  Nitrogen nqcc's in HC4N (MHz).  Calculation was made on the CCSD/TZ2P structure of McCarthy et al. [1].
   










Calc.
Expt. [1]
   






14N Xaa - 3.425 - 3.279
Xbb 0.354 0.490 *
Xcc 3.071 2.790 *
|Xab| 2.543
 
RMS 0.199 (9.1 %)
RSD 0.030 (1.3 %)
 
Xxx 1.632
Xyy 3.071
Xzz - 4.703
ETA 0.306
Øz,a 26.69
Øa,CN 25.95
Øz,CN   0.74
 
 
* Calculated here from Xaa and Xbb - Xcc = -2.300(5) MHz [1].
 
 
Table 3. Structure parameters (Å and degrees).  CCSD(T)/cc-pVTZ and CCSD/TZ2P [1].
 
CCSD(T) CCSD
HC(1) 1.081 1.082
C(1)C(2) 1.331 1.327
C(2)C(3) 1.292 1.292
C(3)C(4) 1.427 1.439
C(4)N 1.162 1.155
HC(1)C(2) 121.1 121.3
HC(1)C(4) 116.0 116.2
C(1)C(2)C(3) 178.0 178.0
C(1)C(4)N 178.2 178.0
 
 
[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).

 








 








Table of Contents



Molecules/Nitrogen
 

 













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Last Modified 24 Nov 2003