HNCO
	Deuterium, Nitrogen, and Oxygen
	Nuclear Quadrupole Coupling Constants
		in Isocyanic Acid
	2H, 14N, and 17O nqcc's have been measured in isocyanic acid [1-4].
	Calculation of the nqcc's was made here on the "modified substitution" molecular structure of Yamada [5].  These calculated nqcc's are compared with the experimental values in Tables 1-6.  Structure parameters are given in Table 7.
	In Tables 1-6, 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 of the model for calculation of the nqcc's:  B3LYP/6-31G(df,3p) for deuterium, B3PW91/6-311+G(df,pd) for nitrogen, and B1LYP/6-311++G(3df,3p) and MP4(SDQ)/6-311++G(3df,3pd) for oxygen.
	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 DNCO (kHz).     PDF     Calc. Expt. [1]     2H Xaa   53.2   57.6(54) Xbb   92.6   84.9(38) Xcc - 145.8 - 142.5(38) |Xab| 207.0   RMS 5.5 (5.7 %) RSD 1.1 (0.9 %)   Xxx - 135.0 - 136.2 * Xyy - 145.8 - 142.5 Xzz 280.8 278.7 ETA 0.038 0.023 Øz,a 47.7 46.9 Øa,ND 49.2 49.2 Øz,ND   1.5   2.3
	* Calculated here from the experimental diagonal nqcc's and the calculated off-diagonal nqcc.
	Table 2.  Nitrogen nqcc's in DNCO (MHz).     PDF     Calc. Expt. [1]     14N Xaa 2.138 2.1237(15) Xbb - 0.569 - 0.5528(18) Xcc - 1.569 - 1.5709(18) |Xab| 1.008     RMS 0.012 (0.9 %) RSD 0.030 (1.3 %)   Xxx - 0.903 - 0.890 * Xyy - 1.569 - 1.5709 Xzz 2.472 2.461 ETA 0.269 0.277 Øz,a 18.3 18.5 Øa,ND 49.2 49.2 Øz,ND 30.8 30.7
	* Calculated here from the experimental diagonal nqcc's and the calculated off-diagonal nqcc.
	Table 3.  Nitrogen nqcc's in HNCO (MHz).     Calc. Expt. [2]     14N Xaa 2.083 2.056(11) Xbb - 0.514 - 0.473 Xcc - 1.569 - 1.583 |Xab| 1.078     RMS 0.030 (2.2 %) RSD 0.030 (1.3 %)
	Table 4.  Nitrogen nqcc's in HNC17O (MHz).     Calc. Expt. [3]     14N Xaa 2.084 2.051(13) Xbb - 0.515 - 0.4725(68) Xcc - 1.569 - 1.578 |Xab| 1.077     RMS 0.031 (2.3 %) RSD 0.030 (1.3 %)
	Table 5.  Oxygen nqcc's in DNCO (MHz).     PDF   Calc = B1LYP/6-311++G(3df,3p)     Calc. Expt. [3]     17O Xaa - 3.284 - 3.276(24) Xbb - 0.131 - 0.176(13) Xcc 3.415 3.452 |Xab| 0.378     RMS 0.034 (1.5 %) RSD 0.041 (1.4 %)   Xxx - 0.086 - 0.133 * Xyy 3.415 3.452 Xzz - 3.328 - 3.319 Øz,a 6.7 6.8 Øa,CO 1.9 1.9 Øz,CO 4.8 4.9
	* Calculated here from the experimental diagonal nqcc's and the calculated off-diagonal nqcc.
	Table 6.  Oxygen nqcc's in DNCO (MHz).     PDF   Calc = MP4(SDQ)/6-311++G(3df,3pd)     Calc. Expt. [3]     17O Xaa - 3.318 - 3.276(24) Xbb - 0.175 - 0.176(13) Xcc 3.493 3.452 |Xab| 0.316     RMS 0.034 (1.5 %) RSD 0.027 (0.93 %)   Xxx - 0.144 - 0.144 * Xyy 3.493 3.452 Xzz - 3.349 - 3.309 Øz,a 5.7 5.8 Øa,CO 1.9 1.9 Øz,CO 3.8 3.9
	* Calculated here from the experimental diagonal nqcc's and the calculated off-diagonal nqcc.
	Table 7.  Molecular structure parameters, rs [5] (Å and degrees). HN 0.9946 NC 1.2140 CO 1.1664 HNC 123.9 NCO 172.6
	[1] N.Heineking, M.C.L.Gerry, and H.Dreizler, Z.Naturforsch. 44a,577(1989); H.Dreizler, Z.Naturforsch. 47a,342(1992).
	[2] W.H.Hocking, M.C.L.Gerry, and G.Winnewisser, Can.J.Phys. 53,1869(1975).
	[3] M.C.L.Gerry, S.J.Howard, N.Heineking, and H.Dreizler, Z.Naturforsch. 44a,1187(1989).
	[4] S.G.Kukolich, A.C.Nelson, and B.S.Yamanashi, J.Amer.Chem.Soc. 93,6769(1985).
	[5] K.Yamada, J.Mol. Spectrosc. 79,323(1980).
	ClNCO		HNCS		HNCSe		HNSO
	Table of Contents
	Molecules/Deuterium
	Molecules/Nitrogen
	Molecules/Oxygen
						DNCO.html
						Last Modified 24 Nov 2004