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.  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 (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 Øz,a   1.94 Øa,CI   1.94 Øz,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 Øz,a   1.79 Øa,CI   1.79 Øz,CI      0
	Table 4.  CH3I  Molecular structure parameters (Å 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.Margulès, 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.Pietilä, 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.Margulès, K.Kyllönen, A.-M.Ahonen, H.Sarkkinen, S.Alanko, H.Mäder, 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) Å,  CH = 1.085(3) Å, 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