C4N2H10
		Nitrogen
	Nuclear Quadrupole Coupling Constants
	in Piperazine  Heq, Hax
	Calculation of the nitrogen nqcc's in Piperazine, eq-ax was made here on molecular structures given by B3P86/6-31G(3d,3p) and MP2/6-311+G(2d,2p) optimizations, with Cs symmetry assumed.  These nqcc's are shown in Tables 1 and 2.  Structure parameters are compared in Table 3, rotational constants in Table 4.
	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(-Heq) nqcc's in Piperazine, eq-ax (MHz).  Calculation was made on the (1) B3P86/6-31G(3d,3p) and (2) MP2/6-311+G(2d,2p) optimized structures.     Calc. (1) Calc. (2) Expt.     Xaa 2.219 2.166 Xbb 2.750 2.753 Xcc - 4.969 - 4.919 |Xac| 0.818 0.871   RSD 0.030 (1.3 %) 0.030 (1.3 %)   Xxx 2.311 2.272 Xyy 2.750 2.753 Xzz - 5.061 - 5.025 ETA 0.087 0.096 Øz,a 83.58 83.10
	Table 2.  14N(-Hax) nqcc's in Piperazine, eq-ax (MHz).  Calculation was made on the (1) B3P86/6-31G(3d,3p) and (2) MP2/6-311+G(2d,2p) optimized structures.     Calc. (1) Calc. (2) Expt.     Xaa - 3.622 - 3.615 Xbb 2.757 2.777 Xcc 0.864 0.838 |Xab| 2.956 2.958   RSD 0.030 (1.3 %) 0.030 (1.3 %)   Xxx 2.332 2.314 Xyy 2.757 2.777 Xzz - 5.089 - 5.091 ETA 0.084 0.091 Øz,a 26.40 26.52
	Table 3.  Piperazine, eq-ax.  Heavy atom and N-H molecular structure parameters (Å and degrees).  Complete structures are given here in Z-matrix format.   ropt (1) = B3P86/6-31G(3d,3p) optimization. ropt (2) = MP2/6-311+G(2d,2p) optimization.   ropt (1) ropt (2)         Ne is N-Heq NeC 1.4564 1.4629         Na is N-Hax CC 1.5248 1.5235 NaC 1.4597 1.4656 N-Heq 1.0131 1.0102 N-Hax 1.0170 1.0133 CNeC 111.26 110.59 CNaC 111.15 110.76 Heq- - - Hax * 4.1117 4.1085        * rs(Heq - - - Hax) = 4.138 Å [1]
	Table 4.  Piperazine, eq-ax.  Rotational Constants (MHz).  Normal Species.   ropt (1) = B3P86/6-31G(3d,3p) optimization. ropt (2) = MP2/6-311+G(2d,2p) optimization.     Calc. ropt (1) Calc. ropt (2)   Expt. [1] A   4771.7   4767.0 4733.114(5) B   4560.0   4559.2 4528.456(5) C   2636.4   2638.9 2618.952(5)
	[1] P.Ottaviani, W.Caminati, A.Millemaggi, J.Mol.Struct. 780-781,22(2006).
	Piperidine		Pyrazine
	Table of Contents
	Molecules/Nitrogen
						Piperazine.html
						Last Modified 22 Feb 2006