CH3CBr3
		Bromine
	Nuclear Quadrupole Coupling Constants
		in Methylbromoform
	The microwave spectrum of methylbromoform was assigned by Li et al. [1].  A partial ro structure - with assumptions for C-CH3 geometry - was derived.
	Calculation of the bromine nqcc tensors in methylbromoform were made here on an ropt structure given by MP2/6-311+G(3df,3pd) optimization, and on this same structure but with CBr and CCBr ro parameters of Li et al. (ropt/ro).  Calculated nqcc tensors are given in Tables 1 - 4, structure parameters in Table 5.
	In Tables 1 and 2, Xuu is the component of the nqcc tensor along the threefold symmetry axis.  Corresponding to the atomic coordinates given below in Table 5, Xvv and Xww are the components along the v- and w- axes for the Br atom in the uv-plane.  Subscripts x,y,z refer to the principal axes of the nqcc tensor.  The y-axis is chosen coincident with the w-axis.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.  In Tables 3 and 4, a,b,c refer to inertial axres.
	RSD is the residual standard deviation of calibration of the B1LYP/TZV(3df,3p) model for calculation of the efg's/nqcc's.
	Table 1.  79Br nqcc's in CH3C79Br3 (MHz).  Calculation was made on the ropt and ropt/ro structures.   Calc  ropt Calc  ropt/ro Expt. Xuu - 222.88 - 249.49 Xvv 533.63 556.44 Xww - 310.75 - 306.95 |Xuv| 276.98 237.49   RSD 1.58 (0.39 %) 1.58 (0.39 %)   Xxx - 313.45 - 314.15 Xyy - 310.75 - 306.95 Xzz 624.20 621.10 ETA - 0.0043 - 0.0012 Øz,u 71.89 74.76 Øu,CBr 70.36 72.3 Øz,CBr   1.53   2.4
	Table 2.  81Br nqcc's in CH3C81Br3 (MHz).  Calculation was made on the ropt and ropt/ro structures.   Calc  ropt Calc  ropt/ro Expt. Xuu - 186.21 - 208.44 Xvv 445.83 464.89 Xww - 259.62 - 256.45 |Xuv| 231.41 190.22   RSD 1.38 (0.40 %) 1.38 (0.40 %)
	Table 3.  Bromine nqcc's in CH3C79Br281Br (MHz).  Calculation was made on the ropt and ropt/ro structures.   Calc ropt Calc ropt/ro Expt. Xaa(79Br) - 100.14 - 91.49 Xbb 322.54 340.60 Xcc - 222.40 - 249.11 |Xab| * 365.21 373.53 |Xac| 138.70 118.89 |Xbc| 240.51 206.08   RSD 1.58 (0.39 %) 1.58 (0.39 %)   Xaa(81Br) 446.63 465.53 Xbb - 259.62 - 256.45 Xcc - 187.01 - 209.08 |Xac| - 230.32 197.13   RSD 1.38 (0.40 %) 1.38 (0.40 %)
	* Product XabXacXbc is positive.
	Table 4.  Bromine nqcc's in CH3C79Br81Br2 (MHz).  Calculation was made on the ropt and ropt/ro structures.   Calc ropt Calc ropt/ro Expt. Xaa(79Br) - 310.75 - 306.95 Xbb 532.67 555.67 Xcc - 221.92 - 248.72 |Xbc| 278.29 238.57   RSD 1.58 (0.39 %) 1.58 (0.39 %)   Xaa(81Br) 269.46 284.56 Xbb - 82.85 - 75.79 Xcc - 186.61 - 208.77 |Xab| * 305.82 312.63 |Xac| 199.88 171.16 |Xbc| 115.53   98.90   RSD 1.38 (0.40 %) 1.38 (0.40 %)
	* Product XabXacXbc is positive.
	Table 5.  Methylbromoform.  Structure parameters, ropt and ropt/ro (Å and degrees).     ropt  ropt/ro C-C 1.5132  --> 1.5132 CBr 1.9409 1.927(8) CH 1.0880  --> 1.0880 CCBr 109.64 107.7(8) CCH 109.31  --> 109.31
	[1] Y.S.Li, K.L.Kizer, and J.R.Durig, J.Mol.Spectrosc. 42.430(1972).
	CH3CH2Br		CH3Br		CH2Br2		CHBr3
	Table of Contents
	Molecules/Bromine
						CH3CBr3.html
						Last Modified 9 June 2014