CH3CH2NH2
	Nitrogen
	Nuclear Quadrupole Coupling Constants
		in Ethylamine
	Calculation of the nitrogen nqcc tensors in ethylamine - anti and gauche - was made on structures obtained by MP2/aug-cc-pVTZ optimization.  These are compared with the experimental nqcc's in Tables 1 and 2. Molecular structure parameters are given in Table 3.
		anti				gauche
				Egauche < Eanti
				by 0.70 kJ/mole
				at MP2/aug-cc-pVTZ
				level of theory
	In Tables 1 and 2, 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 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.   Ø (degrees) is the angle between its subscripted parameters.  ETA = (Xxx - Xyy)/Xzz.
	Table 1. Nitrogen nqcc's in anti CH3CH2NH2 (MHz).  Calculation was made on MP2/aug-cc-pVTZ optimized structure.     Calc. Expt. [1]     14N Xaa - 1.835 - 1.65122(301) Xbb - 0.198 - 0.1473(34) Xcc 2.033 1.7985 * |Xab| 3.655   RMS 0.174 (14.5 %) RSD 0.030 (1.3 %)   Xxx 2.729 Xyy 2.033 Xzz - 4.762 ETA - 0.146 Øz,CN 109.5
	* Calculated here from zero trace condition.
	Table 2. Nitrogen nqcc's in gauche CH3CH2NH2 (MHz).  Calculation was made on MP2/aug-cc-pVTZ optimized structure.     Calc. Expt. [2]     14N Xaa 2.441 2.268(43) Xbb 0.443 0.426 * Xcc - 2.884 - 2.694 * Xab 0.523 Xac 0.272 Xbc - 2.884   RMS 0.149 (8.3 %) RSD 0.030 (1.3 %)   Xxx 2.686 Xyy 2.015 Xzz - 4.701 ETA - 0.143 Øz,CN 107.9
	* Calculated here from experimental Xaa and Xbb - Xcc = 3.120(35) MHz.
	Table 2.  CH3CH2NH2 Molecular structure parameters, MP2/aug-cc-pVTZ opt (Å and degrees). anti-CH3CH2NH2  C  C,1,B1  H,1,B2,2,A1  H,1,B3,2,A2,3,D1,0  H,1,B4,2,A3,3,D2,0  H,2,B5,1,A4,3,D3,0  H,2,B6,1,A5,3,D4,0  N,2,B7,1,A6,3,D5,0  H,8,B8,2,A7,1,D6,0  H,8,B9,2,A8,1,D7,0       Variables:  B1=1.52440502  B2=1.090604  B3=1.09088024  B4=1.090604  B5=1.09064722  B6=1.09064722  B7=1.46300806  B8=1.01368062  B9=1.01368062  A1=110.62561772  A2=111.2343473  A3=110.62561772  A4=109.75928437  A5=109.75928437  A6=115.35466609  A7=109.98343609  A8=109.98343609  D1=120.18546965  D2=-119.62906069  D3=-178.52865947  D4=-61.84227984  D5=59.81453035  D6=58.30027837  D7=-58.30027837   gauche-CH3CH2NH2    C  C,1,B1  H,1,B2,2,A1  H,1,B3,2,A2,3,D1,0  H,1,B4,2,A3,3,D2,0  H,2,B5,1,A4,3,D3,0  H,2,B6,1,A5,3,D4,0  N,2,B7,1,A6,3,D5,0  H,8,B8,2,A7,1,D6,0  H,8,B9,2,A8,1,D7,0       Variables:  B1=1.51776452  B2=1.08855338  B3=1.08936107  B4=1.09113633  B5=1.09614461  B6=1.09047827  B7=1.46518624  B8=1.01289974  B9=1.01379884  A1=110.21387581  A2=111.03443024  A3=110.54315651  A4=109.44060465  A5=109.64582009  A6=109.67921442  A7=110.69064814  A8=109.84021891  D1=120.86636322  D2=-119.43986026  D3=-177.23320045  D4=-60.04799746  D5=57.83449188  D6=-179.7417793  D7=63.01642908
	[1] A.J.Apponi, M.Sun, D.T.Halfen, L.M.Ziurys, and H.S.P.Müller, Astrophys. J. 673,1240(2008).
	[2] E.Fischer and I.Botskor, J.Mol.Spectrosc. 104,226(1984).
	E.Fischer and I.Botskor, J.Mol.Spectrosc. 91,116(1982):  In trans (anti) conformer, X+ = 1.62 ± 0.035 and X- = 1.89 ± 0.08 MHz.
	CH3NH2
	Table of Contents
	Molecules/Nitrogen
						CH3CH2NH2.html
						Last Modified 3 Oct 2005