CHF2I







































Iodine



Nuclear Quadrupole Coupling Constants


in Difluoroiodomethane


 









 









Calculation of the 127I nqcc tensor in difluoroiodomethane was made here on molecular structures given by MP2/6-311+G(d,p), MP2/6-311+G(2d,p), and MP2/6-311G(3d,3p) optimizations; and on these same structures but with empirically corrected re CF and CH bond lengths.  These nqcc's are compared with the experimental values in Tables 1 - 3.  Structure parameters are given in Table 4, rotational constants in Table 5.


 









In Tables 1 - 3, subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  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 the average of the magnitudes of the experimental nqcc's).  RSD is the calibration residual standard deviation of the B1LYP/6-311G(df,p) model for calculation of the nqcc's, which may be taken as an estimate of the uncertainty in the calculated nqcc's.


 









 









   







Table 1. 127I nqcc's in CHF2I (MHz).  

 







Calc (1) was made on the MP2/6-311+G(d,p) optimized molecular structure.

Calc (2) was made on this same structure but with empirically corrected CF and CH bond lengths.

 









Calc (1)
Calc (2)
  Expt. [1]
   







Xaa - 1807.3 - 1794.0 - 1817.9153(33)

Xbb
  955.6
  949.5
  966.1092(32)

Xcc
  851.6
  844.5
  851.8060(32)

|Xac|
  551.5
  549.1
  570.2074(78)

 







RMS
  8.6 (0.71 %)
17.4 (1.43 %)



RSD
15.2 (1.23 %)
15.2 (1.23 %)



 







Xxx
  961.5
  954.2
  949.5893(42)

Xyy
  955.6
  949.5
  966.1092(32)

Xzz - 1917.1 - 1903.7 - 1915.6986(42)

ETA - 0.003043 - 0.002487
0.0086234(28)

Øz,a
11.27
11.30
10.6457(1)

Øa,CI
11.07
11.01



Øz,CI
  0.20
  0.29



 
 







 









 









   







Table 2. 127I nqcc's in CHF2I (MHz).  

 







Calc (1) was made on the MP2/6-311+G(2d,p) optimized molecular structure.

Calc (2) was made on this same structure but with empirically corrected CF and CH bond lengths.

 









Calc (1)
Calc (2)
  Expt. [1]
   







Xaa - 1793.6 - 1777.4 - 1817.9153(33)

Xbb
  949.4
  942.0
  966.1092(32)

Xcc
  844.1
  835.4
  851.8060(32)

|Xac|
  554.8
  551.8
  570.2074(78)

 







RMS
17.6 (1.45 %)
28.8 (2.38 %)



RSD
15.2 (1.23 %)
15.2 (1.23 %)



 







Xxx
  956.0
  947.2
  949.5893(42)

Xyy
  949.4
  942.0
  966.1092(32)

Xzz - 1905.5 - 1889.2 - 1915.6986(42)

ETA - 0.003451 - 0.002720
0.0086234(28)

Øz,a
11.40
11.45
10.6457(1)

Øa,CI
11.18
11.11



Øz,CI
  0.22
  0.34



 
 






   









 









   







Table 3. 127I nqcc's in CHF2I (MHz).  

 







Calc (1) was made on the MP2/6-311+G(3d,3p) optimized molecular structure.

Calc (2) was made on this same structure but with empirically corrected CF and CH bond lengths.

 









Calc (1)
Calc (2)
  Expt. [1]
   







Xaa - 1800.4 - 1784.0 - 1817.9153(33)

Xbb
  952.8
  945.2
  966.1092(32)

Xcc
  847.6
  838.8
  851.8060(32)

|Xac|
  555.7
  552.7
  570.2074(78)

 







RMS
13.0 (1.07 %)
24.2 (2.00 %)



RSD
15.2 (1.23 %)
15.2 (1.23 %)



 







Xxx
  959.5
  950.5
  949.5893(42)

Xyy
  952.8
  945.2
  966.1092(32)

Xzz - 1912.2 - 1895.7 - 1915.6986(42)

ETA - 0.003504 - 0.002837
0.0086234(28)

Øz,a
11.38
11.43
10.6457(1)

Øa,CI
11.17
11.09



Øz,CI
  0.21
  0.33



 
 







 









 













Table 4.  CHF2I  Structure parameters (Å and degrees).
 



r (1) = MP2/6-311+G(d,p) opt

r (2) = r (1) with corrected CF and CH bond lengths.
 


Point Group CS
  r (1)   r (2)





CI 2.1617 2.1617
CH 1.0881 1.0875
CF 1.3462 1.3387
HCI 109.08 109.08
FCI 110.08 110.08
FCF 108.25 108.25
 

r (1) = MP2/6-311+G(2d,p) opt
r (2) = r (1) with corrected CF and CH bond lengths.




  r (1)   r (2)



CI 2.1407 2.1407
CH 1.0866 1.0875
CF 1.3481 1.3387
HCI 109.30 109.30
FCI 110.11 110.11
FCF 108.19 108.19
 


r (1) = MP2/6-311+G(3d,3p) opt

r (2) = r (1) with corrected CF and CH bond lengths.






  r (1)   r (2)





CI 2.1533 2.1533

CH 1.0829 1.0875

CF 1.3485 1.3387

HCI 109.04 109.04

FCI 110.02 110.02

FCF 108.14 108.14



 









 














Table 5.  CHF2I  Rotational constants (MHz).  
 




r (1) = MP2/6-311+G(d,p) opt

r (2) = r (1) with corrected CF and CH bond lengths.







  r (1)   r (2)       Expt. [1]






A 10091.2 10199.4 10139.33667(26)

B   2060.4   2064.7   2089.440949(59)

C   1769.4   1775.5   1791.825733(47)
 
 


r (1) = MP2/6-311+G(2d,p) opt

r (2) = r (1) with corrected CF and CH bond lengths.






A 10072.5 10208.1 10139.33667(26)

B   2091.1   2096.6   2089.440949(59)

C   1791.4   1799.2   1791.825733(47)
 
 


r (1) = MP2/6-311+G(3d,3p) opt

r (2) = r (1) with corrected CF and CH bond lengths.






A 10068.8 10207.6 10139.33667(26)

B   2073.1   2078.6   2089.440949(59)

C   1778.3   1786.4   1791.825733(47)



 









 









[1] C.T.Dewberry, Z.Kisiel, and S.A.Cooke, J.Mol.Spectrosc. 261,82(2010).


 









 









CH3I CH2FI CF3I



CH3Br CH2FBr CHF2Br CF3Br


CH3Cl CH2FCl CHF2Cl CF3Cl


 









 









Table of Contents





Molecules/Iodine





 









 














CHF2I.html






Last Modified 24 March 2010