HNCS			PDF
	Deuterium and Nitrogen
	Nuclear Quadrupole Coupling Constants
		in Isothiocyanic Acid
	Calculation of the D and N nqcc tensors in isothiocyanic acid was made here on the equilibrium molecular structure of Ross et al. [1], and on the substitution structure of Yamada et al. [2].  These are compared with the experimental nqcc's in Tables 1 - 3.  Structure parameters are given in Table 4.
	In Tables 1 - 3, 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 model for calculation of the nqcc's, B3LYP/6-31G(df,3p) for deuterium, and B3PW91/6-311+G(df,pd) for nitrogen.
	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.  The nqcc y-axis is chosen coincident with the inertia c-axis, these are perpendicular to the plane of the molecule.  Ø (degrees) is the angle between its subscripted parameters. ETA = (Xxx - Xyy)/Xzz.
	Table 1.  Deuterium nqcc's in DNCS (kHz).  Calculation was made on the re and rs molecular structures.     Calc / re Calc / rs Expt. [3,4]     Xaa   77.9 100.0   94.8(26) Xbb   56.2   41.9   40.5(14) Xcc - 134.1 - 141.9 - 135.3(14) |Xab| 198.0 207.9   RMS 13.3 (15 %) 4.9 (5.4 %) RSD   1.1 (0.9 %) 1.1 (0.9 %)   Xxx - 131.2 - 138.9 - 135.3(14) Xyy - 134.1 - 141.9 - 135.3(14) Xzz 265.3 280.8 270.6(28) ETA 0.011 0.010 Øz,a 43.43 41.0 41.2(15) Øa,ND 44.99 42.4 Øz,ND   1.56   1.4
	Table 2.   14N nqcc's in DNCS (MHz).  Calculation was made on the re and rs molecular structures.     Calc / re Calc / rs Expt. [3,4]     Xaa 1.134 1.319 1.2135(15) Xbb - 0.498 - 0.624 - 0.5930(9) Xcc - 0.636 - 0.695 - 0.6206(9) |Xab| 1.249 1.118   RMS 0.072 (8.9 %) 0.077 (9.5 %) RSD 0.030 (1.3 %) 0.030 (1.3 %)   Xxx - 1.174 - 1.134 - 1.599(60) Xyy - 0.636 - 0.695 - 0.6206(9) Xzz 1.810 1.829 2.220(60) ETA - 0.298 - 0.240 Øz,a 28.42 24.5 30.9(16) Øa,ND 44.99 42.4 Øz,ND 16.57 17.9
	Table 3.  14N nqcc's in HNCS (MHz).  Calculation was made on the re and rs molecular structures.     Calc / re Calc / rs Expt. [1,2]     Xaa 1.091 1.282 1.1651(23) Xbb - 0.455 - 0.587 - 0.5284(17) Xcc - 0.636 - 0.695 - 0.6367(16) |Xab| 1.277 1.149    RMS 0.060 (7.8 %) 0.083 (10.6 %) RSD 0.030 (1.3 %) 0.030 (1.3 %)   Xxx - 1.174 - 1.134 - 1.591(60) Xyy - 0.636 - 0.695 - 0.6367(16) Xzz 1.810 1.829 2.228(60) ETA - 0.298 - 0.240 Øz,a 28.42 25.4 31.8(16) Øa,NH 44.99 43.3 Øz,NH 16.57 17.9
	For both D and N, the calculated (on re structure) and experimental Xcc are in good agreement.  There are large discrepancies, however, for Xaa and Xbb.  Large-amplitude bending vibration in the ab-plane has been noted by Heineking and Dreizler [3] and Ross et al. [1].
	Table 4.  HNCS Molecular structure parameters, re [1] and rs [2] (Å and degrees).    re [1]  rs [2] HN 1.00178 0.993 NC 1.20046 1.207 CS 1.57480 1.5665 HNC 129.3525 131.7 NCS 174.399 173.8
	[1] S.C.Ross, M.Niedenhoff, and K.M.T.Yamada, J.Mol.Spectrosc. 164,432(1994).  "... large-amplitude [in plane] HNC bending mode."
	[2] K.Yamada, M.Winnewisser, G.Winnewisser, L.B.Szalanski, and M.C.L.Gerry, J.Mol.Spectrosc. 79,295(1980).
	[3] N.Heineking and H.Dreizler, Z.Naturforsch. 47a,511(1992).  "low-lying, large amplitude bending vibration."
	[4] M.Rodler, S.Jans-Bürli, M.Oldani, and A.Bauder, Chem.Phys.Lett. 142,10(1987).
	K.Yamada, M.Winnewisser, G.Winnewisser, L.B.Szalanski, and M.C.L.Gerry, J.Mol.Spectrosc. 78,189(1979):  Xaa = 1.114 MHz.
	L.B.Szalanski, M.C.L.Gerry, G.Winnewisser, K.Yamada, and M.Winnewisser, Can.J.Phys. 56,1297(1978): DNCS, Xaa = 1.19(6) MHz and Xbb - Xcc < 0.05 MHz.
	HNCO		ClNCO		HNCSe		HNSO
	Table of Contents
	Molecules/Deuterium
	Molecules/Nitrogen
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						Last Modified 30 April 2009