Ground State of NH

Nitrenes, the nitrogen analogs of carbenes, are too reactive for isolation under ordinary conditions. The ground state of NH, and of most nitrenes, is a triplet. Aryl nitrenes have been trapped at 77 K,186 the more reactive alkyl nitrenes in matrices at 4 K.187... 

Nitrenes,239 R—N, are the nitrogen analogs of carbenes, and most of what we have said about carbenes also applies to them. Nitrenes are too reactive for isolation under ordinary conditions. Alkyl nitrenes have been isolated by trapping in matrices at 4 K,24n while aryl nitrenes, which are less reactive, can be trapped at 77 K.241 The ground state of NH, and probably of most nitrenes,242 is a triplet, though nitrenes can be generated in both triplet and singlet states. In additions of EtOOC—N to C=C double bonds two species are involved,... 

We may imagine the ground state of NH, reacting with either the ground or excited state of Sc to form a doublet with a nonplanar structure in which the bonding electron on Sc" " is formally either 4s or 3da. 

Fitting a Rydberg-Klein-Rees-Vanderslice potential function for the ground state of NH (cf. p. 54) to the empirical Lippincott potential function (see [39]) resulted in Dq = 3.45 0.14eV [40]. 

NHg, NH+, and NHj. The radical NHa was the first polyatomic free radical to be observed experimentally, and it has since been extensively studied spectroscopically. Bender and Schaefer 458 have referenced calculations on NHa prior to 1970, and have presented results for the most accurate calculations yet carried out, to which we return below. However, del Bene,459 at about the same time, reported the results of an SCF study, using small (STO-3G) or (ST04-31G) basis sets. The predicted zBi ground state of the radical has 0 = 108°, J (N—H) = 1.01 A, and for the Mi state 0 = 144°, 7 (N—H) = 0.98 A. 

The reaction of ground-state nitrene NH(X S ) with molecular oxygen in argon or xenon matrices at temperatures of 20 K yields imine peroxide ... 

Fig. 6.3. Contour maps of the ground-state electronic charge distributions for the second- and thrid-row diatomic hydrides showing the positions of the interatomic surfaces. The first set of diagrams (a) also includes a plot for the ground state of the Hj molecule. The outer density contour in these plots is 0.001 au. The remaining contours increase in valne according to the scale given in the Appendix (Table A2). (a) The left-hand side 2, LiH 2, BeH 2, BH 2 right-hand side CH n, NH 2", OH n, HF 2+. (b)The left-hand side NaH 2-, MgH 2+, AIH 2+, SiH right-hand side PH 2-, SH "H. HCI 2. ...

Calculations were originally carried out (2 ) for the lowest states of Hz, LiH, BH, NH, and HF and the corresponding deuterated molecules with the LCAO-MO wavefunction of Coulson for Hz (11) and the LCAO-MO-SCF functions of Hansil (12) for the other molecules. These wavefunctions contain a minimum basis set of inner and valence shell Slater-type orbitals with the orbital exponents optimized at the experimental equilibrium intemuclear distance. The S states are the ground states of the respective molecules except in the case of NH. 

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