CH3C(=O)-N=C=O
		Nitrogen
	Nuclear Quadrupole Coupling Constants
		in Acetylisocyanate
	The microwave spectrum of acetylisocyanate was investigated by Uchida et al. [1].  The 14N quadrupole splitting, however, was not resolvable.
	Calculation of the 14N nqcc tensor was made here on ropt molecular structures given by  B3LYP/6-311+G(3df,3pd) and MP2/6-311+G(3df,3pd) optimization.  Calculated nqcc's are given in Table 1.  Structure parameters are given in Table 2.  Rotational constants, electric dipole moments, and a,b,c coordinates of methyl carbon are given in Table 3.
	In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor; 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 molecular plane.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
	RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of nitrogen efg's/nqcc's.
	Table 1.  14N nqcc's in Acetylisocyanate (MHz).  Calculation was made on molecular structures given by (1) B3LYP/6-311+G(3df,3pd) and (2) MP2/6-311+G(3df,3pd) optimization.     Calc. (1) Calc. (2) Expt.     Xaa 2.725 2.725 Xbb - 1.682 - 1.650 Xcc - 1.043 - 1.075 |Xab| 0.230 0.175 RSD 0.030 (1.3 %) 0.030 (1.3 %)   Xxx - 1.694 - 1.657 Xyy - 1.043 - 1.075 Xzz 2.737 2.732 ETA - 0.238 - 0.213 Øz,a   2.97   2.29 Øa,N=C 18.87 20.16 Øz,N=C 21.84 22.45
	Table 2.  Acetylisocyanate.  Optimized molecular structure parameters, ropt (Å and degrees).   B3LYP/6-311+G(3df,3pd)  and  MP2/6-311+G(3df,3pd)    C  O,1,B1  C,1,B2,2,A1  H,3,B3,1,A2,2,D1,0  H,3,B4,1,A3,2,D2,0  H,3,B5,1,A4,2,D3,0  N,1,B6,2,A5,3,D4,0  C,7,B7,1,A6,2,D5,0  O,8,B8,7,A7,1,D6,0          B3LYP         MP2    B1=1.20012923    B2=1.50434670    B3=1.08973387    B4=1.08515671    B5=1.08973387    B6=1.42168667    B7=1.21641889    B8=1.15729334    A1=124.13767117    A2=108.61610629    A3=112.30710126    A4=108.61610629    A5=122.39812371    A6=130.56507151    A7=173.81447744    D1=58.13938542    D2=180.    D3=-58.13938542    D4=180.    D5=0.0    D6=180.  B1=1.20615243  B2=1.50091678  B3=1.087788  B4=1.08370978  B5=1.087788  B6=1.42142032  B7=1.22618444  B8=1.16470643  A1=124.14858926  A2=108.45026488  A3=112.01723836  A4=108.45026488  A5=122.71720731  A6=127.63034012  A7=173.19575549  D1=58.22853015  D2=180.  D3=-58.22853015  D4=180.  D5=0.  D6=180.
	Table 3.  Acetylisocyanate.  Rotational constants (MHz), dipole moments * (D), and a,b,c coordinates of the methyl carbon. ropt(1) = B3LYP/6-311+G(3df,3pd) optimization. ropt(2) = MP2/6-311+G(3df,3pd) optimization. ropt(1) ropt(2) Expt [1] A 10960.5 10914.7 10773.160(25) B   2166.3   2185.3   2222.693(5) C   1829.1   1841.4   1862.934(5) |µa| 1.59 1.57 |µb| 2.15 2.14 |µc| zero (symm) zero (symm)   |a| /Å 2.180 2.190 2.183(3) |b| /Å 0.766 0.738 0.706(9) |c| /Å zero (symm) zero (symm) 0.080(87) * B3PW91/6-311+G(df,pd) calculation on ropt structure.
	[1] Y.Uchida, M.Toyoda, N.Kuze, and T.Sakaizumi, J.Mol.Spectrosc. 256,163(2009).
	HNCO		ClNCO		BrNCO		INCO
	Difluoroisocyanato Silane			Ethylisocyanate
	Methyldifluoroisocyanate Silane			tert-Butylisocyanate
	Table of Contents
	Molecules/Nitrogen
						CH3CONCO.html
						Last Modified 29 Nov 2013