




















ClF_{2}CCHF_{2} 


PDF














Chlorine 



Nuclear
Quadrupole Coupling Constants 


in
1Chloro1,1,2,2Tetrafluoroethane

































Calculation of the chlorine nqcc's in
1chloro1,1,2,2trifluoroethane were 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. 












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 caxis, 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 ClF_{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} 

15.72 

14.28 




X_{bb} 
 
53.87 
 
52.43 




X_{cc} 

38.16 

38.16 




X_{ab} 

44.89 

45.84 













X_{xx} 

37.72 

37.61 




X_{yy} 

38.16 

38.16 




X_{zz} 
 
75.88 
 
75.77 




ETA 

0.006 

0.007 




Ø_{z,a} 

63.89 

63.02 




Ø_{a,CCl} 

65.13 

64.49 




Ø_{z,CCl} 

1.24 

1.47 













































Table 2. ^{37}Cl
nqcc's in ClF_{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} 

9.90 

8.79 




X_{bb} 
 
39.98 
 
38.87 




X_{cc} 

30.07 

30.07 




X_{ab} 

37.17 

37.79 



































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. 


F 
2 
R5 
3 
A5 
6 
D5 


F 
2 
R5 
3 
A5 
6 
 D5 












MP2 Angles 
B3P86 Angles 













R1 
1.7394 





R2 
1.525 





R3 
1.3415 





R4 
1.091 





R5 
1.3394 





A1 
112.48 
112.87 




A3 
109.44 
109.70 




A4 
109.80 
109.40 




A5 
108.03 
108.19 




D3 
59.69 
59.85 




D5 
58.14 
58.27 


























[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}ClCHF_{2} 
CH_{3}CCl_{3} 


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


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
























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Molecules/Chlorine 






























CF2ClCHF2.html 






Last
Modified 14 August 2003 









