Nuclear Quadrupole Coupling Constants

in Selenoformaldehyde


Calculation was made here of the deuterium nqcc tensor in selenoformaldehyde on the substitution structure of Brown et al. [1].  These are given in Tables 1 and 2.  Structure parameters are given in Table 3.



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 a-axis is coincident with the twofold symmetry axis.  The nqcc y-axis is chosen coincident with the inertia c-axis, which is perpendicular to the plane of the molecule.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
RSD is the calibration residual standard deviation for the B3LYP/6-31G(df,3p) model for calculation of the nqcc's, which may be taken as an estimate of the uncertainty in the calculated nqcc's.



Table 1.  Deuterium nqcc's in D2C=Se (kHz).  Calculation was made on the rs structure [1].


2H Xaa - 19.8
Xbb 109.1
Xcc - 89.3
Xab ± 119.7
RSD 1.1 (0.9 %)
Xxx - 91.3
Xyy - 89.3
Xzz 180.6
ETA - 0.0107
Øz,a 120.85
Øa,CD 121.03
Øz,CD     0.18



Table 2.  Deuterium nqcc's in HDC=Se (kHz).  Calculation was made on the rs structure [1].


2H Xaa   - 8.8
Xbb   98.1
Xcc - 89.3
Xab ± 125.0
RSD 1.1 (0.9 %)
Table 3.  H2C=Se Structure parameters, rs [1] C=Se = 1.7531 Å
CH = 1.0904 Å
  HCH = 117.93o

[1] R.D.Brown, P.D.Godfrey, D.McNaughton, and P.R.Taylor, J.Mol.Spectrosc. 120,292(1986).



H2Si=S H2C=O H2C=S H2Si=O



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Last Modified 7 June 2010