(NF2)2
	Nitrogen
	Nuclear Quadrupole Coupling Constants
		in gauche Tetrafluorohydrazine
	Calculations of the nitrogen nqcc tensor in gauche tetrafluorohydrazine (C2) were made on molecular structures derived ab initio by MP2/6-311+G(3df) and MP2/aug-cc-pVTZ optimizations.  These are compared in Table 1 with the experimental nqcc's of Frank et al. [1].  Structure parameters are given in Table 2, rotational constants and dipole moments in Table 3.
	In Table 1, subscripts a,b,c refer to principal axes of the inertia tensor; x,y,z to principal axes of the nqcc tensor.  ETA = (Xxx - Xyy)/Xzz.  Øz,NN is the angle between the z-principal axis and the NN bond axis.  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, which may be taken as an estimate of the uncertainty in the calculated nqcc's.
	Table 1.  14N nqcc's in (NF2)2 (MHz).  Calculation was made on the (1) MP2/6-311+G(3df) and (2) MP2/aug-cc-pVTZ optimized structures.     Calc (1) Calc (2) Expt [1]     Xaa 2.324 2.278 2.246(12) Xbb - 0.470 - 0.469 - 0.454 * Xcc - 1.854 - 1.809 - 1.792(5) Xab 2.174 2.185 Xac +/- 1.282 +/- 1.286 Xbc -/+ 5.819 -/+ 5.734   RMS 0.059 (3.9 %) 0.023 (1.5 %) RSD 0.030 (1.3 %) 0.030 (1.3 %)   Xxx 2.632 2.594 Xyy 4.974 4.916 Xzz - 7.606 - 7.510 ETA 0.308 0.309 Øz,NN 124.3 124.7
	* Calculated here from zero trace condition.
	Table 2.  Guache tetrafluorohydrazine, (NF2)2. Molecular structure parameters.   Point Group: C2 MP2/6-311+G(3df) MP2/aug-cc-pVTZ  N  N,1,B1  F,1,B2,2,A1  F,1,B3,2,A2,3,D1,0  F,2,B2,1,A1,3,D2,0  F,2,B3,1,A2,3,D3,0       Variables:  B1=1.45533949  B2=1.36539809  B3=1.36972517  A1=100.93407911  A2=107.17952203  D1=-107.64455232  D2=174.57406957  D3=66.92951725  N  N,1,B1  F,1,B2,2,A1  F,1,B3,2,A2,3,D1,0  F,2,B2,1,A1,3,D2,0  F,2,B3,1,A2,3,D3,0       Variables:  B1=1.46314255  B2=1.37377528  B3=1.37681081  A1=100.70245674  A2=107.11257135  D1=-107.20165135  D2=174.13756941  D3=66.93591805
	Table 3.  Guache tetrafluorohydrazine, (NF2)2.  Rotational constants (MHz) and dipole moment (D).  ropt(1) = MP2/6-311+G(3df) and ropt(2) = MP2/aug-cc-pVTZ ropt(1) ropt(2)   Expt [1] A 5645.3 5599.6 5576.1995(1) B 3250.3 3223.5 3189.43277(8) C 2862.7 2840.4 2813.16955(8)   |µc| 0.28 0.31 0.256(4)
	[1] U.E.Frank, W.Herdeg, P.N.Ghosh, and W.Hüttner, Mol.Phys. 69,33(1990).
	Hydrazine
	Table of Contents
	Molecules/Nitrogen
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						Last Modified 28 Jan 2011