(CH3)2NN=O
	Nitrogen
	Nuclear Quadrupole Coupling Constants
		in Dimethylnitrosamine
	Calculation of the nitrogen nqcc's in dimethylnitrosamine was made here on a molecular structure given by B3LYP/cc-pVTZ optimization.  These are compared with the experimental nqcc's of Heineking and Dreizler [1] in Tables 1 and 2; and those of Guarnieri et al. [2] in Tables 3 and 4.  Structure parameters are given in Z-matrix format in Table 5, rotational constants in Table 6.
	In Tables 1 - 4, 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.
	RMS is the root mean square differene between calculated and experimental nqcc's (percent of average experimental nqcc).  RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of the efg's/nqcc's.
	Table 1. Amino nitrogen nqcc's in (CH3)2NN=O (MHz).  Calculation was made on the B3LYP/cc-pVTZ ropt molecular structure.   Calc. Expt. [1]     14N Xaa 1.986 2.0210(25) Xbb 2.107 2.1287(31) Xcc - 4.092 - 4.1497(31) |Xab| 0.470   RMS 0.033 (1.2 %) RSD 0.030 (1.3 %)     Xxx 1.572 Xyy 2.520 Xzz - 4.092 ETA 0.232 Øz,c    0
	Table 1. Nitroso nitrogen nqcc's in (CH3)2NN=O (MHz).  Calculation was made on the B3LYP/cc-pVTZ ropt molecular structure.   Calc. Expt. [1]     14N Xaa 1.870 1.9054(25) Xbb - 5.482 - 5.4118(27) Xcc 3.612 3.5064(27) |Xab| 1.346   RMS 0.075 (2.1 %) RSD 0.030 (1.3 %)     Xxx 2.108 Xyy 3.612 Xzz - 5.720 ETA 0.263 Øz,a 79.94 Øa,bi* 87.26 Øz,bi   7.32
	* "bi" is bisector of NN=O angle.
	Table 3. Amino nitrogen nqcc's in (CH3)2N15N=O (MHz).  Calculation was made on the B3LYP/cc-pVTZ ropt molecular structure.   Calc. Expt. [2]     14N Xaa 1.994 1.92(10) Xbb 2.098 2.09(10) Xcc - 4.092 - 4.11(10) |Xab| 0.471   RMS 0.04 (1.6 %) RSD 0.030 (1.3 %)
	Table 4. Nitroso nitrogen nqcc's in (CH3)215NN=O (MHz).  Calculation was made on the B3LYP/cc-pVTZ ropt molecular structure.   Calc. Expt. [2]     14N Xaa 1.870 1.83(10) Xbb - 5.482 - 5.55(10) Xcc 3.612 3.72(10) |Xab| 1.345   RMS 0.08 (2.1 %) RSD 0.030 (1.3 %)
	Table 5.  Dimethylnitrosamine.  B3LYP/cc-pVTZ optimized molecular structure parameters, ropt (Å and degrees).    N  N,1,B1  O,2,B2,1,A1  C,1,B3,2,A2,3,D1,0  H,4,B4,1,A3,2,D2,0  H,4,B5,1,A4,2,D3,0  H,4,B6,1,A5,2,D4,0  C,1,B7,2,A6,3,D5,0  H,8,B8,1,A7,2,D6,0  H,8,B9,1,A8,2,D7,0  H,8,B10,1,A9,2,D8,0  B1=1.3265921  B2=1.22186221  B3=1.4541258  B4=1.08630965  B5=1.09039556  B6=1.09039556  B7=1.44750646  B8=1.0868103  B9=1.09200323  B10=1.09200323  A1=114.81412723  A2=120.63540955  A3=108.55615551  A4=110.33673004  A5=110.33673004  A6=116.95618512  A7=107.47315665  A8=111.04216193  A9=111.04216193  D1=0.  D2=180.  D3=59.35126677  D4=-59.35126677  D5=180.  D6=0.  D7=119.47072768  D8=-119.47072768
	Table 6.  Dimethylnitrosamine.  Rotational Constants (MHz), Calc = B3LYP/cc-pVTZ.  Centrifugal distortion constants (kHz), Calc = B3LYP/cc-pVTZ.   Calc   Expt. [1] A 9050. 9053.74(15) B 4610. 4613.91(11) C 3176. 3170.33(11)   Delta_J 0.686 0.7(71) Delta_JK 8.18    --- Delta_K 0.0615 21.7(22) delta_J 0.187 1.086(26) delta_K 1.65 14.8(11)
	[1] N.Heineking and H.Dreizler, Z.Naturforsch. 48a,570(1993).
	[2] A.Guarnieri, F.Rohwer, and F. Scappini, Z.Naturforsch. 30a,904(1975).
	A.Guarnieri and R.Nicolaisen, Z.Naturforsch. 34a,620(1979).
	F.Scappini, A.Guarnieri, H.Dreizler, and P.Rademacher, Z.Naturforsch. 27a,1329(1972).
	Methyl ethyl nitrosamine				Methyl propyl nitrosamine
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