H2NCHO		PDF
	Nitrogen
	Nuclear Quadrupole Coupling Constants
		in Formamide
	Nitrogen nqcc's in formamide were determined by Kirchoff and Johnson [1], a substitution structrure by Hirota et al. [2].
	Calculation of the nqcc's was made here on the substitution structure and on ab initio structures given by HF/6-311++G(3df,3pd) and HF/aug-cc-pVTZ optimizations.  Calculated and experimental nqcc's are compared in Tables 1 and 2.  Structure parameters are given in Table 3 rotational constants in Table 4.
	In Tables 1 and 2, subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
	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 B3PW91/6-311+G(df,pd) model for calculation of nitrogen nqcc's.
	Table 1.  Nitrogen nqcc's in NH2CHO (MHz).  Calculation was made on the substitution structure of Hirota et al. [2].     Calc. Expt. [1]     14N Xaa 1.972 1.98(3) Xbb 1.915 1.87(2) Xcc - 3.888 - 3.85(2) |Xab| 0.062   RMS 0.04 (1.3 %) RSD 0.030 (1.3 %)   Xxx 1.875 Xyy 2.012 Xzz - 3.888 ETA 0.035 Øx,a 57.27 Øa,NC 25.13 Øx,NC 32.15
	Table 2.   14N nqcc's in NH2CHO (MHz).  Calculation was made on the (1) HF/6-311++G(3df,3pd) and (2) HF/aug-cc-pVTZ optimized structures.     Calc. (1) Calc. (2) Expt. [1]     Xaa 1.962 1.963 1.98(3) Xbb 1.918 1.915 1.87(2) Xcc - 3.880 - 3.878 - 3.85(2) |Xab| 0.025 0.022   RMS 0.03 (1.3 %) 0.03 (1.2 %) RSD 0.030 (1.3 %) 0.030 (1.3 %)   Xxx 1.907 1.906 Xyy 1.973 1.972 Xzz - 3.880 - 3.878 ETA 0.017 0.017 Øx,a 65.84 68.63 Øa,NC 24.45 24.48 Øx,NC 41.38 44.15
	Table 3. Molecular structure parameters (Å and degrees).     ropt (1)  HF/6-311++G(3df,3pd) ropt (2)  HF/aug-cc-pVTZ   rs [2] ropt (1) ropt (2) NHc 1.0016 0.9920 0.9918 NHt 1.0015 0.9890 0.9888 CN 1.352 1.3457 1.3461 CO 1.219 1.1861 1.1878 CH 1.098 1.0914 1.0912 HcNC 118.5 119.49 119.51 HtNC 120.0 121.23 121.21 NCO 124.7 124.87 124.87 NCH 112.7 112.90 112.92
	Table 4.  Rotational Constants (MHz).  Normal Species.   ropt (1) = HF/6-311++G(3df,3pd) optimization. ropt (2) = HF/aug-cc-pVTZ(G03) optimization.     Calc. ropt (1) Calc. ropt (2)    Expt. A   7586.3   7579.3 B   1170.0   1168.2 C   1013.6   1012.2
	[1] W.H.Kirchoff and D.R.Johnson, J.Mol.Spectrosc. 45,159(1973).
	[2] E.Hirota, R.Sugisaki, C.J.Nielsen, and G.O.Sørensen, J.Mol. Spectrosc. 49,251(1974).
	H2NCHS		NH2OH		NH2Cl		NH2F
	BH2NH2		BF2NH2		PF2NH2		B2H5NH2
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						Last Modified 12 Jan 2006