NH2CH2C(=O)OH
		Nitrogen
	Nuclear Quadrupole Coupling Constants
	in Glycine
	Calculation of the nitrogen nqcc's in glycine was made here on the molecular structures given by HF/6-311+G(d,p) and HF/6-311++G(3df,3pd) optimizations.  These are compared with the experimental nqcc's [1] in Tables 1 and 2.  Structure parameters are given in Table 3, rotational constants in Table 4.
	Calculation was made on each of the two lowest energy conformers shown below:
		Conformer I				Conformer II
	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.
	RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of nitrogen nqcc's.
	Table 1.  14N nqcc's in Glycine I (MHz).  Calculation was made on (1) HF/6-311+G(d,p) and (2) HF/6-311++G(3df,3pd) optimized structures.     Calc. (1) Calc. (2) Expt. [1]     Xaa - 1.308 - 1.330 - 1.208(9) Xbb - 0.592 - 0.561 - 0.343(8) Xcc 1.900 1.891 1.552(10) |Xab| 4.021 4.005   RMS 0.254 (24 %) 0.243 (24 %) RSD 0.030 (1.3 %) 0.030 (1.3 %)   Xxx 3.087 3.078 Xyy 1.900 1.891 Xzz - 4.987 - 4.969 ETA - 0.238 - 0.239 Øz,a   42.45   42.26 Øa,NC   31.60   31.67 Øz,NC * 105.94 106.07
	* Here and in Table 2, this is the angle between the external (to the H2NC pyrimid and in the ab-plane) z-axis and the NC axis.
	Table 2.  14N nqcc's in Glycine II (MHz).  Calculation was made on (1) HF/6-311+G(d,p) and (2) HF/6-311++G(3df,3pd) optimized structures.     Calc. (1) Calc. (2) Expt.     Xaa 1.750 1.762 1.773(2) Xbb - 3.575 - 3.584 - 3.194(4) Xcc 1.826 1.822 1.421(4) |Xab| 2.645 2.629   RMS 0.321 (15 %) 0.323 (15 %) RSD 0.030 (1.3 %) 0.030 (1.3 %)   Xxx 2.840 2.839 Xyy 1.826 1.822 Xzz - 4.666 - 4.661 ETA - 0.217 - 0.218 Øz,a   67.59   67.74 Øa,NC   37.69   37.61 Øz,NC 105.28 105.34
	Table 3.  Glycine.  Selected molecular structure parameters (Å and degrees).  Complete structures are given here in Z-matrix format: Glycine I and Glycine II.   ropt (1) = HF/6-311+G(d,p) optimization. ropt (2) = HF/6-311++G(3df,3pd) optimization.          Conformer I ropt (1) ropt (2)   CC 1.5154 1.5142 CN 1.4364 1.4352 NH 0.9997 0.9978 CCN 115.53 115.49 CNH 111.18 111.10 CCNH ±59.51 ±59.36        Conformer II CC 1.5270 1.5252 CN 1.4550 1.4527 NH 0.9975 0.9953 CCN 112.80 113.06 CNH 112.78 112.74 CCNH ±118.42 ±118.43
	Table 4.  Glycine.  Rotational Constants (MHz).  Normal Species.   ropt (1) = HF/6-311+G(d,p) optimization. ropt (2) = HF/6-311++G(3df,3pd) optimization.     Calc. ropt (1) Calc. ropt (2)    Expt. [1]    I A 10681.0 10727.8 10341.5279(49) B   3919.1   3930.9   3876.1806(23) C   2961.7   2971.6   2912.3518(16)      II A 10334.4 10375.0 10130.1521(57) B   4103.2   4105.9   4071.5120(17) C   3037.4   3041.9   3007.4852(14)
	[1] F.J.Lovas, Y.Kawashima, J.-U.Grabow, R.D.Suenram, G.T.Fraser, and E.Hirota, Astrophys. 455,L201(1995).
	Related ...
	V.V.Ilyushin, E.A.Alekseev, S.F.Dyubko, R.A.Motiyenko, and F.J.Lovas, J.Mol.Spectrosc. 231,15(2005).
	N-Acetylglycine
	Table of Contents
	Molecules/Nitrogen
						Glycine.html
						Last Modified 23 Feb 2006