CH3I

























 









Iodine


Nuclear Quadrupole Coupling Constants


in Methyliodide


 








 








 








Calculation was made of the 127I nqcc's in methyliodide on an re structure determined by Demaison et al. [1], and on earlier rs structures determined by Mallinson [2] and Duncan and Mallinson [3].  These are compared with the experimental nqcc's [4 - 12] in Tables 1 - 3.  Molecular structure parameters are given in Table 4.

 


 





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.  (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 (percentage of the average of the magnitudes of the experimental nqcc's).  RSD is the calibration residual standard deviation for 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.  Iodine nqcc's in CH3I (MHz).  Calc. = B1LYP/6-311G(df,p).  Calculation was made on the re [1], rs [2], and rs [3] structures.  In Calc. column, Ref. is for the structure on which calculation was made.
   










Calc./Ref.
 Expt./Ref.
   







127I Xaa - 1918.0 [1] - 1934.1306(51)  [4]



- 1919.8 [2] - 1934.11(2)  [5]



- 1924.8 [3] - 1934.13022(39) [6]





- 1934.136(5) [7]





-
1934.080(10) [8]






-
1934.16(2) [9]






- 1934  [10]





-
1934.0 [11]


 







 








 







 
   







Table 2.  Iodine nqcc's in CH2DI (MHz).  Calc. = B1LYP/6-311G(df,p).  Calculation was made on the re structure.
   










Calc.
 Expt. [12]
   







127I Xaa - 1914.7 - 1928.8833(89)


Xbb - Xcc
    - 3.315
    - 3.550(99)


Xbb
  955.7
  962.667


Xcc
  959.0
  966.217


|Xab|
    97.6



 







RMS
10.0 (0.78 %)




RSD
15.2 (1.23 %)



 







Xzz - 1918.0




ETA
     0




z,a
  1.94




a,CI
  1.94




z,CI
     0



 







 








 








   







Table 3.  Iodine nqcc's in CHD2I (MHz).  Calc. = B1LYP/6-311G(df,p).  Calculation was made on the re structure.
   










Calc.
 Expt. [12]
   







127I Xaa - 1915.2 - 1927.6689(99)


Xbb - Xcc
      2.80
      3.027(28)


Xbb
  959.0
  965.348


Xcc
  956.2
  962.321


|Xac|
    89.7



 







RMS
  8.8 (0.69 %)




RSD
23.8 (1.70 %)



 







Xzz - 1918.0




ETA
     0




z,a
  1.79




a,CI
  1.79




z,CI
     0



 

















 



Table 4.  CH3I  Molecular structure parameters ( and degrees).
 





 re [1]  rs [2]  rs [3]






CI 2.1336 2.1358(20) 2.1423(15)

CH 1.0819 1.0840(30) 1.088(2)

HCH 111.40
111.52(25)

HCI 107.62 107.47(20)



 








 








[1] J.Demaison, L.Marguls, and J.E.Boggs, Struct.Chem. 14,159(2003).

[2] P.D.Mallinson, J.Mol.Spetrosc. 55,94(1975).  Substitution structure and, in CH2DI, Xaa = -1928.746(81), Xbb = 962.527(90), and Xcc = 966.219(90) MHz.

[3] J.L.Duncan and P.D.Mallinson, J.Mol.Spetrosc. 39,471(1971).

[4] S.Carocci, A.DiLieto, A.DeFanis, P.Minguzzi, S.Alanko, and J.Pietil, J.Mol.Spectrosc. 191,368(1998).

[5] S.H.Young and S.G.Kukolich, J.Mol.Spectrosc. 114,483(1985).

[6] B.D.Osipov and M.N.Grabois, J.Mol.Spectrosc. 111,344(1985).

[7] D.Boucher, J.Burie, D.Dangoisse, J.Demaison, and A.Dubrulle, Chem.Phys. 29,323(1978).

[8] G.Wlodarczak, D.Boucher, R.Bocquet, and J.Demaison, J.Mol.Spectrosc. 124,53(1987).


[9] J.Burie, D.Boucher, J.Demaison, and A.Dubrulle, Mol.Phys. 32,289(1976).


[10] W.Gordy, J.W.Simmons, and A.G.Smith, Phys.Rev. 74,243(1948).

[11] W.J.O.Thomas, J.T.Cox, and W.Gordy, J.Chem.Phys. 22,1718(1954).

[12] F.Willaert, L.Marguls, K.Kyllnen, A.-M.Ahonen, H.Sarkkinen, S.Alanko, H.Mder, and J.Demaison, J.Mol.Spectrosc. 248,146(2008).

 








R.A.Motiyenko, E.A.Alekseev, A.V.Kryvda, V.G.Gerasimov, and S.F.Dyubko, J.Mol.Spectrosc. 245,81(2007):  In 13CH3I, eqQ = -1934.22584(47) MHz.

G.Wlodarczak, D.Boucher, R.Bocquet, and J.Demaison, J.Mol.Spectrosc. 124,53(1987): In 13CH3I, eqQ = -1934.291(164) MHz, and in CD3I, eqQ = -1928.918(86) MHz.

J.Demaison, D.Boucher, G.Piau, and P.Glorieux, J.Mol.Spectrosc. 107,108(1984): In CD3I, eqQ = -1928.896(43) MHz.

J.L.Duncan, J.Mol.Struct. 6,447(1970): re structure, CI = 2.113(2) ,  CH = 1.085(3) , and HCH = 111o17'(25').  On this structure, calculated Xaa in CH3I is -1899.6 MHz.

J.Gadhi, G.Wlodarczak, J.Legrand, and J.Demaison, Z.Naturforsch. 42a,1241(1987): In CD3I, eqQ = -1928.983(38) MHz.

R.Livingston, B.M.Benjamin, J.T.Cox, and W.Gordy, Phys.Rev. 92,1271(1953):  eQq(131I) = -973(9) MHz.  131I is radioactive with half-life of 8 days.


 









 








CH2I2 CH3Cl CH3Br


 








 








Table of Contents




Molecules/Iodine




 








 













CH3I.html






Last Modified 9 Dec 2008