CH2=C(H)CCCl
		Chlorine
	Nuclear Quadrupole Coupling Constants
		in 4-Chlorobuten-3-yne
	Calculation of the chlorine nqcc's in 4-chlorobuten-3-yne was made on an approximate equilibrium structure derived here by MP2/aug-cc-pVTZ optimization with empirically corrected bond lengths.  These nqcc's are compared with the available experimental values [1] in Table 1.  Structure parameters are given in Table 2, rotational constants in Table 3.
	In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor; 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 molecular symmetry plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
	RSD is the calibration residual standard deviation for the B1LYP/TZV(3df,2p) model for calculation of the chlorine nqcc's, which may be taken as an estimate of the uncertainty in the calculated coupling constants.
	Table 1. Chlorine nqcc's in 4-Chlorobuten-3-yne (MHz).     Calc. Expt. [1]     35Cl Xaa - 77.26 - 76.9(4) Xbb 38.36 Xcc 38.90 |Xab| 15.34   RSD 0.49 (1.1 %)   Xxx 40.35 Xyy 38.90 Xzz - 79.26 ETA - 0.0183 Øz,a 7.42 Øa,CCl 7.44 Øz,CCl 0.02     37Cl Xaa - 60.92 - 60.9(4) Xbb 30.26 Xcc 30.66 |Xab| 11.97   RSD 0.44 (1.1 %)
	Table 2.  4-Chlorobuten-3-yne   Heavy atom structure parameters (Å and degrees).  Complete structure is given here in Z-matix format.   Parameter  reapprox C(1)=C(2) 1.3378 C(2)C(6) 1.4242 C(6)C(7) 1.2077 C(7)Cl 1.6351 C(1)C(2)C(6) 123.68
	Table 3.  4-Chlorobuten-3-yne  Rotational Constants (MHz), 35Cl species.   Calc is on the reapprox molecular structure.     Calc.   Expt. [1] A 42015.8 6875.239(4) B   1412.3 3096.353(2) C   1366.4 2131.950(2)
	[1] F.Karlsson, M.Granberg, and R.Vestin, Acta Chem. Scand. A 29,111(1975).
	CH2=C=C=CHCl		t-1-Chlorobuten-3-yne		2-Chlorobuten-3-yne
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	Molecules/Chlorine
						4Clbuten3yne.html
						Last Modified 29 Nov 2011