F2C=CHCl						PDF
		Chlorine
	Nuclear Quadrupole Coupling Constants
		in 1-Chloro-2,2-difluoroethylene
	The complete 35Cl nqcc tensor in 1-chloro-2,2-difluoroethylene was measured by Stone and Flygare [1].  Chandra [2] derived a ground state effective structure.
	Calculation of the chlorine nqcc's was made on the ground state effective structure, and on a structure derived ab initio as described below.  These nqcc's are compared with the experimental values in Tables 1 and 2.  Structure parameters are given in Table 3.
	In Tables 1 and 2, RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percentage of the average of the magnitudes of the experimental nqcc's).  RSD is the calibration residual standard deviation for the B1LYP/TZV(3df,2p) model for calculation of the chlorine nqcc's.
	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.
	Table 1. Chlorine nqcc's in F2C=CHCl (MHz).  Calculation was made on the effective molecular structure of Chandra [2].     Calc. Expt. [1]     35Cl Xaa - 57.46 - 55.05(10) Xbb 20.83 18.29(8) Xcc 36.63 36.76(10) |Xab| 46.01 46.3(40)   RMS 2.02 (5.5 %) RSD 0.49 (1.1 %)   Xxx 42.10 40.64 Xyy 36.63 36.76 Xzz - 78.72 - 77.40 ETA - 0.015 - 0.050 Øz,a 24.8 25.8(11) Øa,CCl 26.2 Øz,CCl   1.4
	Table 2. Chlorine nqcc's in F2C=CHCl (MHz).  Calculation was made on the ab initio structure, ropt.     Calc. Expt. [1]     35Cl Xaa - 55.19 - 55.05(10) Xbb 18.88 18.29(8) Xcc 36.31 36.76(10) |Xab| 46.48 46.3(40)   RMS 0.44 (1.2 %) RSD 0.49 (1.1 %)   Xxx 41.28 40.64 Xyy 36.31 36.76 Xzz - 77.58 - 77.40 ETA - 0.064 - 0.050 Øz,a 25.73 25.8(11) Øa,CCl 26.45 Øz,CCl   0.72     37Cl Xaa - 55.01 Xbb 18.82 Xcc 36.18 |Xab| 46.32   RSD 0.44 (1.1 %)
	Ab Initio Molecular Structure
	The molecular structure was optimized at the MP2/6-311+G(d,p) level of theory assuming Cs symmetry.  The optimized C=C bond length was then corrected using the equation obtained from linear regression analysis of the data given in Table IX of Ref.[5].  Likewise, the optimized CF bond lengths were corrected by regression analysis of the data given in Table VI of Ref.[4].  For the CCl bond, the structure was optimized at the MP2/6-311+G(2d,p) level and corrected by linear regression analysis of the data given in Table 4 of Ref.[3].  The CH bond lengths were corrected using r = 1.001 ropt, where ropt is obtained by MP2/6-31G(d,p) optimization [6].  Interatomic angles are those given by MP2/6-311+G(2d,p) optimization.
	Table 3.  Molecular structure parameters (Å and degrees).   ro [2]   ropt CCl 1.726 1.7088 CH 1.08 1.0766 C=C 1.30 1.3232 CFc 1.32 1.3080 CFt 1.32 1.3142 C=CCl 122.3 121.96 C=CH 123.8 118.04 C=CFc 125 125.61 C=CFt 125 123.07 FCF 110 111.32
	[1] R.G.Stone and W.H.Flygare, J.Chem.Phys. 49,1943(1968).
	[2] S.Chandra, J.Phys.Chem. 71,1927(1967).
	[3] I.Merke, L.Poteau, G.Wlodarczak, A.Bouddou, and J.Demaison, J.Mol.Spectrosc. 177,232(1996).
	[4] R.M.Villamañan, W.D.Chen, G.Wlodarczak, J.Demaison, A.G.Lesarri, J.C.López, and J.L.Alonso, J.Mol.Spectrosc. 171,223(1995).
	[5] J.Demaison, J.Cosléou, R.Bocquet, and A.G.Lesarri, J.Mol.Spectrosc. 167,400(1994).
	[6] J.Demaison and G.Wlodarczak, Structural Chem. 5,57(1994).
	CH2CHCl		c-CHFCHCl		CH2CCl2		c-ClHCCHCl
	Table of Contents
	Molecules/Chlorine
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						Last Modified 15 July 2004