FNF Radical

Nitrogen

Nuclear Quadrupole Coupling Constants

in FNF Free Radical

Nitrogen nqcc's were first determined in the FNF radical by Frank et al. [1], and revisited by Müller et al. [2]. These latter also derived a "preferred" molecular structure. Calculation was made here of the nqcc's on this structure. These calculated nqcc's are compared with the experimental values in Table 1. Structure parameters are given in Table 2.

In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor. RMS is the root mean square difference between calculated and experimental nqcc's. RSD is the residual standard deviation of calibration of the B3PW91/6-311+G(df,pd) model for calculation of the nqcc's, which may be taken as an estimate of the uncertainty in the calculated nqcc's.


Table 1. ¹⁴N nqcc's in FNF radical (MHz).

		Calc.		Expt. [1]		Expt. [2]

X_aa		5.457		5.495(87)		5.556(41)
X_bb	-	0.493	-	0.667(47)	-	0.710(27)
X_cc	-	4.964	-	4.828(40)	-	4.846(23)

RMS				0.129 (3.5 %)		0.154 (4.1 %)
RSD				0.030 (1.3 %)		0.030 (1.3 %)


Table 2. FNF. Molecular structure parameters [2] (Å and degrees).

	NF	1.34691(68)
	FNF	103.132(20)

[1] U.E.Frank and W.Hüttner, Chem.Phys. 152,261(1991).

[2] H.S.P.Müller, K.Löblein, H.Hübner, W.Hüttner, and J.Brown, J.Mol.Spectrosc. 251,185(2008).

R.D.Brown, F.R.Burden, P.D.Godfrey, and I.R.Gillard, J.Mol.Spectrosc. 25,301(1974): X_aa = 5.59, X_bb = -0.73, X_cc = -4.86 MHz.

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Last Modified 5 March 2008