CH3-SiHF-N=C=O
		Nitrogen
	Nuclear Quadrupole Coupling Constants
		in Methylfluoroisocyanate Silane
	The microwave spectrum of methylfluoroisocyanate silane was observed and assigned by Seifert, Guirgis, et al. [1,2].
	Calculation of the 14N nqcc tensor was made here on ropt molecular structures given by HF/6-31G(3d,3p) and HF/6-311G(3d,3p) optimization, and on a MP3/aug-cc-pVTZ optimized structure derived by Guirgis et al. [2].  These calculated nqcc's are compared with the experimental values [1,2] in Table 1.  Structure parameters  in Z-matrix format for the HF optimizations are compared in Table 2, rotational constants and dipole moments in Table 3, and centrifugal distortion constants in Table 4.  For the MP3 optimization, see Ref. [2].
	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.  ETA = (Xxx - Xyy)/Xzz.  Ø is the angle between its subcripted parameters.
	RMS is root mean square difference between calculated and experimental nqcc's.  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 CH3-SiHF-N=C=O (MHz).  Calculation was made on (1) HF/6-31G(3d,3p), (2) HF/6-311G(3d,3p), and (3) MP3/aug-cc-pVTZ ropt structures.   Calc (1) Calc (2) Calc (3) Expt [1,2] *   Xaa 1.726 1.737 1.811 1.770(7) Xbb - 0.855 - 0.857 - 0.891 - 0.839(36) Xcc - 0.871 - 0.880 - 0.919 - 0.931(36) Xab 0.139 0.121 0.149 Xac - 0.408 - 0.250 - 0.254 Xbc - 0.033 - 0.004 0.002 RMS 0.044 (3.7 %) 0.037 (3.1 %) 0.039 (3.3 %) RSD 0.030 (1.3 %) 0.030 (1.3 %) 0.030 (1.3 %) Xxx - 0.861 - 0.858 - 0.894 Xyy - 0.935 - 0.908 - 0.948 Xzz 1.796 1.766 1.842 ETA 0.0413 0.0285 0.0291 Øz,N=C 6.95 8.33 7.18
	* Xaa, Xbb, Xcc derived here from experimental 1.5Xaa = 2.655(11) and 0.25(Xbb - Xcc) = 0.023(18) MHz.
	Table 2. CH3-SiHF-N=C=O.  HF/6-31G(3d,3p) and HF/6-311G(3d,3p) ropt structure parameters (Å and degrees).  C  Si,1,B1  N,2,B2,1,A1  C,3,B3,2,A2,1,D1,0  O,4,B4,3,A3,2,D2,0  H,2,B5,3,A4,4,D3,0  F,2,B6,3,A5,4,D4,0  H,1,B7,2,A6,3,D5,0  H,1,B8,2,A7,3,D6,0  H,1,B9,2,A8,3,D7,0 HF/6-31G(3d,3p) HF/6-311G(3d,3p)  B1=1.8474159  B2=1.70124874  B3=1.18327343  B4=1.14431429  B5=1.46291508  B6=1.5844807  B7=1.08643881  B8=1.08656174  B9=1.08608598  A1=110.11742251  A2=157.22143802  A3=177.80777346  A4=108.6715672  A5=107.88320335  A6=110.70612224  A7=110.51918747  A8=111.0796777  D1=147.37312784  D2=-179.27358425  D3=-88.36014533  D4=27.88917231  D5=-179.12477079  D6=61.13153467  D7=-58.86481063  B1=1.84616011  B2=1.7032079  B3=1.18108404  B4=1.14017693  B5=1.46447886  B6=1.58238689  B7=1.08405763  B8=1.08443362  B9=1.08378141  A1=109.85429306  A2=155.04342237  A3=177.6985679  A4=109.21623096  A5=107.66011147  A6=110.71229712  A7=110.21230887  A8=110.9222252  D1=-174.71678886  D2=176.30460511  D3=-50.07439864  D4=66.02908308  D5=-178.630018  D6=61.63761453  D7=-58.19207679
	Table 3. CH3-SiHF-N=C=O.  Rotational Constants (MHz) and Dipole Moments (D).  (1) HF/6-31G(3d,3p) and (2) HF/6-311G(3d,3p) ropt structures. Calc (1) Calc (2)   Expt [1] A 6163.7 6340.3 6301.415(45) B 1565.4 1548.0 1535.078(39) C 1342.0 1320.3 1310.485(39) |µa|  2.05  1.93 |µb|  1.40  1.44 |µc|  0.52  0.61
	Table 4. CH3-SiHF-N=C=O.  Quartic Centrifugal Distortion Constants (kHz).  Calc = B3LYP/cc-pVTZ Calc  Expt [1] Delta_J 0.566 0.742(33) Delta_JK 23.7 41.50(14) Delta_K 1.06 - 25.39(10) delta_J 0.0184 0.067(13) delta_K 12.6 25.6(19)
	[1] N.A.Seifert, S.Lobsiger, B.H.Pate, G.A.Guirgis, J.S.Overby, and J.R.Durig, Abstract RC12, 68th International Symposium on Molecular Spectroscopy, 2013.
	[2] G.A.Guirgis, J.S.Overby, T.J.Barker, M.H.Palmer, B.H.Pate, and N.A.Seifert, J.Phys.Chem. A, 119(4),652(2015).
	Methyldifluoroisocyanate Silane			CH3CH2N=C=O		Acetylisocyanate		HNCO
	Difluoroisocyanato Silane			Vinylisocyanate		tert-Butylisocyanate		ClNCO
	Table of Contents
	Molecules/Nitrogen
						CH3SiHFNCO.html
						Last Modified 9 Dec 2016