HSSH
	Sulfur
	Nuclear Quadrupole Coupling Constants
		in Disulfane
	33S nqcc's in H33S32SH were determined by Saleck and Winnewisser [1].  A "partially corrected  equilibrium" molecular structure was derived by Hahn, Behrend, et al. [2,3].
	Calculation of the nqcc tensor was made here on this structure.  Calculated and experimental nqcc's are compared in Table 1.  Structure parameters are given in Table 2, atomic coordinates in Table 3.
	In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor, subscripts 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 nqcc's (percentage of average experimental nqcc).  RSD are the residual standard deviations of calibration of the B3LYP/6-311G(3df,3p) and B3LYP/TZV+(3df,3p) models for calculation of the nqcc's.
	Table 1.  33S nqcc's in H33S32SH (MHz).  Calculation was made on the structure of Behrend et al. [2].     Calc. [a] B3LYP/6-311G(3df,3p) Model. Calc. [b] B3LYP/TZV+(3df,3p) Model.   Calc. [a] Calc. [b] Expt. [1]     Xaa - 36.40 - 36.59 - 36.28(28) Xbb - 5.46 - 5.34     ? 16.063(151) Xcc 41.86 41.92     ? 20.219(139) Xab* - 11.12 - 11.05 Xac* - 3.02 - 2.97 Xbc* - 18.00 - 17.99   RSD 0.39 (1.7 %) 0.35 (1.5 %)   Xxx - 7.03 - 7.00 Xyy - 40.91 - 41.00 Xzz 47.93 48.00 ETA 0.707 0.708 Øz,n**   0.95   0.93 Øx,bi** 18.38 18.66
	* Algebraic signs of the off-diagonal nqcc's correspond to the atomic coordinate given in Table 3.
	** The z-principal axis makes an angle of Øz,n with the normal (n) to the H33SS plane.  The x-axis makes an angle of Øx,bi with the (internal) bisector (bi) of the H33SS angle, and tilts toward H.
	Table 2.  Disulfane.  Molecular structure parameters [2,3] (Å and degrees).   HS 1.3421(2) SS 2.0564(1) HSS 97.88(5) HSSH 90.34(20)
	Table 3.  H33S32SH.  Atomic coordinates.   a (Å) b (Å) c (Å)    H 1.2269 1.2139 0.4111 33S 1.0123 - 0.0396 - 0.0178 32S - 1.0430 - 0.0106 0.0435    H - 1.2583 0.4195 - 1.2094
	1,2-Dithiin		Dimethyl Disulfide
	[1] A.H.Saleck and G.Winnewisser, Z.Naturforsch. 50a,1191(1995).
	[2] J.Hahn, P.Schmidt, K.Reinartz, J.Behrend, G.Winnewisser, and K.M.T.Yamada Z.Naturforsch. 46b, 1338(1991).
	[3] J.Behrend, P.Mittler, G.Winnewisser, and K.M.T.Yamada, J.Mol.Spectrosc. 150,99(1991).
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						Last Modified 23 April 2006