CH2CH3N(H)C(=O)H
	Nitrogen
	Nuclear Quadrupole Coupling Constants
		in N-Ethylformamide trans-synclinal
	Nitrogen nqcc's in N-ethylformamide, and a heavy atom substitution structure were determined by Ohba et al. [1].  Calculation of the nqcc's was made here on this structure complemented by MP2/6-311+G(d,p) optimization for the hydrogen structure, and on a structure given by HF/aug-cc-pVTZ optimization.  Calculated and experimental nqcc's are compared in Table 1.  Structure parameters are given in Table 2, rs/ropt atomic coordinates in Table 3, rotational constants in Table 4.
	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.  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 efg's/nqcc's.
	Table 1. 14N nqcc's in N-Ethylformamide (MHz).  Calculation was made on the rs/ropt structure (the derivation of which is briefly discussed below), and on an ropt structure given by HF/aug-cc-pVTZ optimization.   Calc rs/ropt Calc ropt Expt. [1]   Xaa 1.389 1.384 1.3794(13) Xbb 0.845 0.795 0.8171(20) Xcc - 2.234 - 2.179 - 2.1965(20) Xab - 0.735 - 0.592 Xac - 1.536 - 1.569 Xbc - 2.318 - 2.265 RMS 0.027 (1.9 %) 0.017 (1.1 %) RSD 0.030 (1.3 %) 0.030 (1.3 %) Xxx 1.896 1.740 Xyy 2.117 2.183 Xzz - 4.013 - 3.923 ETA 0.055 0.113
	Table 2.  Molecular structure parameters, rs/ropt and ropt = HF/aug-cc-pVTZ optimization. (Å and degrees).  The rs/ropt structure was derived with substitution parameters were held fixed, while hydrogen atom parameters were determined by partial optimization at the MP2/6-311+G(d,p) level of theory.  C  O,1,B1  N,1,B2,2,A1  C,3,B3,1,A2,2,D1,0  C,4,B4,3,A3,1,D2,0  H,3,B5,1,A4,2,D3,0  H,1,B6,2,A5,3,D4,0  H,4,B7,3,A6,1,D5,0  H,4,B8,3,A7,1,D6,0  H,5,B9,4,A8,3,D7,0  H,5,B10,4,A9,3,D8,0  H,5,B11,4,A10,3,D9,0    rs/ropt    ropt  B1=1.2173  B2=1.3757  B3=1.439  B4=1.5155  B5=1.00888616  B6=1.10448059  B7=1.09430186  B8=1.09332725  B9=1.0924911  B10=1.09445652  B11=1.09414336  A1=124.02  A2=121.27  A3=113.2  A4=117.88106556  A5=123.4769532  A6=107.84966238  A7=107.38619512  A8=110.08425781  A9=110.50669638  A10=110.83813921  D1=-1.99  D2=-82.17  D3=-174.99295103  D4=179.3530347  D5=154.94222193  D6=39.32471617  D7=59.90859603  D8=179.63296236  D9=-60.29538215  B1=1.19185096  B2=1.34234003  B3=1.45100172  B4=1.52249681  B5=0.99027358  B6=1.09118643  B7=1.08263965  B8=1.07924826  B9=1.08212832  B10=1.08410104  B11=1.08448513  A1=125.42622743  A2=123.29927667  A3=113.32719559  A4=117.45192601  A5=121.85446325  A6=107.63531568  A7=107.58796065  A8=110.55833374  A9=110.16227437  A10=111.10365887  D1=-2.13060465  D2=-87.7293937  D3=-176.55919949  D4=179.34834596  D5=149.97218516  D6=34.25154375  D7=60.43270112  D8=-179.83435772  D9=-60.05872636
	Table 3.  N-Ethylformamide.  Atomic coordinates, rs/ropt.     a (Å)   b (Å)   c (Å) C 1.281521 0.280872 - 0.252688 O 1.511462 - 0.835396 0.174971 N 0.078050 0.930079 - 0.101902 C - 1.034828 0.297267 0.555192 C - 1.817173 - 0.628812 - 0.354234 H - 0.037555 1.821794 - 0.559429 H 2.024607 0.889378 - 0.798052 H - 1.680720 1.085157 0.954626 H - 0.636495 - 0.264133 1.404619 H - 1.167410 - 1.422596 - 0.730068 H - 2.646926 - 1.090075 0.190359 H - 2.228511 - 0.080670 - 1.207163
	Table 4. N-Ethylformamide.  Rotational constants (MHz):  rs/ropt and ropt = HF/aug-cc-pVTZ.    rs/ropt   ropt     Expt. [1] A 9873.9 10590.3 9904.8373(6) B 3555.3   3373.2 3521.0995(2) C 3002.7   2935.8 2984.9808(2)
	[1] K.Ohba, T.Usami, Y.Kawashima, and E.Hirota, J.Mol.Struct. 744-747,815(2005).
	V.Vaquero-Vara, V.Alstadt, T.P.Sewatsky, J.L.Claughton, I.A.Finneran, S.T.Shipman, B.H.Pate, and D.W.Pratt, J.Mol.Spectros. 335,102(2017): Xaa = 1.379(2), Xbb = 0.816(13), Xcc = -2.195(13) MHz
	Formamide		Acetamide		Dimethylamine
	N-Methylacetamide			N-Ethylformamide cis-ac
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	Molecules/Nitrogen
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						Last Modified 6 July 2017