HOCH2CN
	Nitrogen
	Nuclear Quadrupole Coupling Constants
		in Hydroxyacetonitrile
	Calculation of the nitrogen nqcc tensors in the gauche and trans conformers of hydroxyacetonitrile was made on molecular structures given by MP2/aug-cc-pVTZ optimization with approximate re CC and CN bond lengths.  These calculated nqcc's are compared with the experimental values for the gauche conformer [1] in Table 1, and are given for the trans conformer in Table 2.  Structure parameters are given in Table 3 in Z-matrix format, rotational constants and dipole moments in Table 4, quartic centrifugal distortions constants in Table 5.
	trans Cs			gauche C1			cis Cs
	Local Minimum			Global Minimum			TS Saddle Point
	At the B3LYP/cc-pVTZ and MP2/cc-pVTZ levels of theory respectively, trans hydroxyacetonitrile is higher in energy than gauche by 7.7/7.1 kJ/mol, while cis is higher than gauche by 5.3/5.9 kJ/mol.  The cis conformer - with one imaginary frequency - is a saddle point on the PE surface, presumable connecting equivalent mirror image gauche conformers.
	In Tables 1 and 2, RMS is the root mean square difference between calculated and experimental diagonal nqcc's.  RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of the nitrogen nqcc's.
	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 (degrees) is the angle between its subscripted parameters.
	Table 1. Nitrogen nqcc's in gauche HOCH2CN (MHz).  Calculation was made on a molecular structure given by MP2/aug-cc-pVTZ optimization with approximate re CC and CN bond lengths.     Calc. Expt [1]     14N Xaa - 3.561 - 3.63 Xbb 1.697 1.64 Xcc 1.864 1.99 Xab 2.248 Xac 0.011 Xbc - 0.055   RMS 0.097 (4.0 %) RSD 0.030 (1.3 %)   Xxx 2.531 Xyy 1.861 Xzz - 4.392 ETA 0.152 Øz,CN 0.31
	Table 2. Nitrogen nqcc's in trans HOCH2CN (MHz).  Calculation was made on a molecular structure given by MP2/aug-cc-pVTZ optimization with approximate re CC and CN bond lengths.     Calc. Expt     14N Xaa - 3.564 Xbb 1.826 Xcc 1.828 Xab 2.122   RSD 0.030 (1.3 %)   Xxx 2.552 Xyy 1.828 Xzz - 4.380 ETA - 0.165 Øz,a 18.88 Øa,CN 18.54 Øz,CN   0.34
	Table 3.  Hydroxyacetonitrile.  MP2/aug-cc-pVTZ optimized molecular structure parameters (Å and degrees).  Approximate re bond lengths for CC and CN are given in parentheses.    N  C,1,B1  C,2,B2,1,A1  O,3,B3,2,A2,1,D1,0  H,4,B4,3,A3,2,D2,0  H,3,B5,2,A4,1,D3,0  H,3,B6,2,A5,1,D4,0 trans gauche  B1=1.16963183   (1.1552)  B2=1.46354819   (1.4640)  B3=1.41816573  B4=0.96343489  B5=1.09243859  B6=1.09243859  A1=178.13717936  A2=107.94457755  A3=107.62920186  A4=108.15046671  A5=108.15046671  D1=180.  D2=180.  D3=-58.75396373  D4=58.75396373  B1=1.17062545   (1.1559)  B2=1.47132978   (1.4715)  B3=1.41360373  B4=0.96360414  B5=1.09189219  B6=1.0873618  A1=178.20693054  A2=112.48707348  A3=108.43138072  A4=108.41569433  A5=108.85726323  D1=-52.38789233  D2=60.63215579  D3=72.35692477  D4=-170.15610614
	Table 4.  Hydroxyacetonitrile.  Rotational Constants (MHz) and Dipole Moments * (D). trans gauche Calc Expt Calc   Expt [1] A 35375 33515 33605.57(22) B   4873   4853   4840.44(4) C   4401   4396   4377.60(3) |µa|   4.10   2.36 |µb|   2.90   1.34 |µc|   0 (symmetry)   1.34 * B3PW91/6-311+G(df,pd) dipole moments calculated on molecular structures given by MP2/aug-cc-pVTZ optimization with approximate re CC and CN bond lengths
	Table 5.  Hydroxyacetonitrile.  B3LYP/cc-pVTZ and MP2/cc-pVTZ Calculated Quartic Centrifugal Distortion Constants (kHz). trans gauche B3LYP MP2 B3LYP MP2 Delta_J 2.57 2.64 3.06 3.08 Delta_JK - 58.5 - 59.7 - 63.9 - 65.0 Delta_K 1048. 1035. 950. 956. delta_J 0.529 0.554 0.652 0.664 delta_K 15.6 16.1 17.7 18.0 D_J 2.51 2.58 3.00 3.01 D_JK - 58.2 - 59.4 - 63.5 - 64.6 D_K 1048. 1035. 950. 956. d_1 - 0.528 - 0.554 - 0.652 - 0.664 d_2 - 0.0284 - 0.0303 - 0.0340 - 0.0348
	[1] G.Cazzoli, D.G.Lister, and A.M.Mirri, J.Chem.Soc. Faraday Trans. II 69,569(1973).
	L.Margulès, R.A.Motiyenko, and J.C.Guillemin, Abstract TI13, 68th OSU International Symposium on Molecular Spectroscopy, 2013.
	CH3CN		FCH2CN		ClCH2CN
	Table of Contents
	Molecules/Nitrogen
						HOCH2CN.html
						Posted 12 April 2013
						Last Modified 22 Dec 2013