




















ClH_{2}CCHF_{2} 


PDF














Chlorine 



Nuclear
Quadrupole Coupling Constants 


in
1Chloro2,2Difluoroethane

































Calculation of the chlorine nqcc's in
1chloro2,2difluoroethane was made on structures with bond lengths
derived ab initio
by the methods of the Lille group, as described below.
Interatomic angles used are those given by (1) MP2/6311+G(d,p),
and (2) B3P86/6311+G(3d,3p) optimization. Calculated nqcc's are
shown in Tables 1 and 2. Structure
parameters are given in ZMatrix format in Table 3.













Calculation was made also on
MP2/augccpVTZ r_{opt} and approximate r_{e}
structures. See results here. 












In Tables 1 and 2, 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 yaxis is chosen coincident with the
inertia baxis, these are perpendicular to the molecular symmetry
plane.
Ø (degrees) is the angle between its subscripted
parameters. ETA = (X_{xx}  X_{yy})/X_{zz}. 
































Table 1. ^{35}Cl
nqcc's in ClH_{2}CCHF_{2} (MHz). Calculation was
made on the ab initio
structure with interatomic angles given by (1) MP2/6311+G(d,p),
and (2) B3P86/6311+G(3d,3p) optimization. 













Calc. (1)


Calc. (2) 

Expt. 











X_{aa} 
 
19.52 
 
21.42 




X_{bb} 

39.80 

39.80 




X_{cc} 
 
20.28 
 
18.38 




X_{ac} 

57.54 

57.30 













X_{xx} 

37.64 

37.41 




X_{yy} 

39.80 

39.80 




X_{zz} 
 
77.44 
 
77.22 




ETA 

0.028 

0.031 




Ø_{z,a} 

44.81 

44.24 




Ø_{a,CCl} 

45.76 

45.16 




Ø_{z,CCl} 

0.95 

0.91 













































Table 2. ^{37}Cl
nqcc's in ClH_{2}CCHF_{2} (MHz).
Calculation was made on the ab
initio structure with interatomic angles given by (1)
MP2/6311+G(d,p), and (2) B3P86/6311+G(3d,3p) optimization. 













Calc. (1)


Calc. (2) 

Expt. 











X_{aa} 
 
15.90 
 
17.38 




X_{bb} 

31.37 

31.37 




X_{cc} 
 
15.47 
 
13.99 




X_{ac} 

45.35 

45.14 



































Molecular
Structure













The molecular structure was optimized
at the MP2/6311+G(d,p) level of theory assuming C_{s}
symmetry. The optimized CC single bond length was then corrected
using the equation obtained from linear regression analysis of the data
given in Table IX of Ref.[3]. Likewise, the optimized CF bond
lengths were corrected by regression analysis of the data given in
Table VI of Ref.[2]. For the CCl bond, the structure was
optimized at the MP2/6311+G(2d,p) level and corrected by linear
regression analysis of the data given in Table 4 of Ref.[1]. The
CH bond lengths were corrected using r = 1.001 r_{opt},
where r_{opt} is obtained by MP2/631G(d,p) optimization
[4]. Interatomic angles used in the calculation are
those given by (1) MP2/6311+G(d,p) and (2) B3P86/6311+G(3d,3p)
optimization. 





















Table 3. Structure parameters
(Å and degrees). 










Cl 








C 
1 
R1 






C 
2 
R2 
1 
A1 




F 
3 
R3 
2 
A3 
1 
D3 


F 
3 
R3 
2 
A3 
1 
 D3 


H 
3 
R4 
2 
A4 
1 
180. 


H 
2 
R5 
3 
A5 
6 
D5 


H 
2 
R5 
3 
A5 
6 
 D5 












MP2 Angles 
B3P86 Angles 













R1 
1.7642 





R2 
1.5036 





R3 
1.3520 





R4 
1.093 





R5 
1.088 





A1 
111.75 
112.81 




A3 
110.81 
111.21 




A4 
111.23 
110.66 




A5 
108.66 
109.05 




D3 
59.75 
60.00 




D5 
59.80 
59.84 


























[1] I.Merke, L.Poteau,
G.Wlodarczak, A.Bouddou, and J.Demaison, J.Mol.Spectrosc. 177,232(1996). 


[2] 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) 


[3] J.Demaison,
J.Cosléou, R.Bocquet, and A.G.Lesarri, J.Mol.Spectrosc.
167,400(1994). 


[4] J.Demaison and G.Wlodarczak,
Structural Chem. 5,57(1994). 






















CH_{3}Cl 
_{}CH_{3}CH_{2}Cl 
CH_{2}ClCH_{2}F_{} 
CH_{3}CCl_{3} 


CF_{2}ClCH_{3} 
CF_{2}ClCHF_{2} 
CF_{2}ClCH_{2}F 
CF_{2}ClCF_{3} 


_{}CF_{3}Cl 
CH_{2}ClCF_{3} 
























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Molecules/Chlorine 






























CH2ClCHF2.html 






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