O=C=C(H)Cl
	Chlorine
	Nuclear Quadrupole Coupling Constants
		in Chloroketene
	Calculation of the Cl nqcc tensors in chloroketene was made on an ro structure derived by Gerry et al. [1], and on an approximate equilibrium structure given by MP2/aug-cc-pVTZ optimization with empirically corrected bond lengths.  These calculated nqcc's are compared with experimental values [1] in Table 1.  Structure parameters are given in Table 2.
	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.
	RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percent of average experimental nqcc's).  RSD is the residual standard deviation of calibration of the B1LYP/TZV(3df,2p) model for calculation of the chlorine nqcc's.
	Table 1. Chlorine nqcc's in O=C=C(H)Cl (MHz).  Calculation was made on the ro and approximate re structures.     Calc / ro Calc / re Expt. [1]     35Cl Xaa - 47.69 - 47.74 - 47.321(38) Xbb   3.89   4.48   4.134 Xcc 43.80 43.26 43.186 |Xab| 56.70 55.93 56.18(65)   RMS 0.44 (1.4 %) 0.32 (1.0 %) RSD 0.49 (1.1 %) 0.49 (1.1 %)   Xxx 40.39 40.09 40.2(15) Xyy 43.80 43.26 43.19(4) Xzz - 84.20 - 83.36 - 83.4(10) ETA 0.040 0.038 Øz,b 57.23 57.51 57.30(13) Øb,ClC 56.34 56.05 Øz,ClC   0.88   1.46   37Cl Xaa - 37.91 - 37.95 - 37.789(72) Xbb   3.38   3.85   3.766 Xcc 34.52 34.10 34.023 |Xab| 44.54 43.93   RMS 0.37 (1.5 %) 0.11 (0.5 %) RSD 0.44 (1.1 %) 0.44 (1.1 %)
	Table 2. Chloroketene molecular structure parameters ro, Str II [1], and approximate re (Å and degrees).     ro   re CH 1.079 1.0749 CCl 1.726 1.7255 HCCl 123.2 119.74 HCC 117.0 120.89 C=C 1.316 1.3176 C=O 1.161 1.1587 C=C=O 180. 179.92
	[1] M.C.L.Gerry, W.Lewis-Bevan, and N.P.C.Westwood, J.Chem.Phys. 79,4655(1983).
	Ketene		Bromoketene		Cyanoketene
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	Molecules/Chlorine
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						Last Modified 8 Dec 2011