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We have investigated the photoionization of ammonia borane (AB) and determined adiabatic ionization energy to be 9.26 � 0.03 eV for the X + 2 E ! X 1 A 1 transition. Although the threshold photoelectron spectrum appears at first glance to be similar to the one of the isosteric ethane, the electronic situation differs markedly, due to different orbital energies. In addition, an appearance energy AE 0K -(NH 3 BH 3 , NH 3 BH 2 + ) = 10.00 � 0.03 eV has been determined, corresponding to the loss of a hydrogen atom at the BH 3 -site. From the data, a 0 K bond dissociation energy for the BÀ H bond in the cation of 71.5 � 3 kJ mol À 1 was derived, whereas the one in the neutral compound has been estimated to be 419 � 10 kJ mol À 1 .

Experimental Auger electron spectra of C, N, and O 1s ionized and excited HCNO are compared with theoretical counterparts. A simple minimal-basis LCAO approach provides reliable estimates for the significantly different Auger transition rates.

Biradical formation vs. π‐bonding: The low‐valent, highly reactive pnictogen compounds PnCH3 (Pn=As, Sb) have been generated in situ by controlled homolysis of Pn(CH3)3 in the gas phase and investigated by photoelectron–photoion coincidence spectroscopy. This allowed us to establish trends in nature's strategy to stabilize low‐valent pnictogen species either by tautomerization with concomitant multiple bond formation (HPn=CH2) or by biradical formation (Pn−CH3). The graphic illustrates the energetic steps separating the isomers of these fundamentally important group 15 compounds. More information can be found in the Research Article by C. Lichtenberg, P. Hemberger, I. Fischer and co‐workers (DOI: 10.1002/chem.202300637).

Due to their unusual electronic structure, the biradical m-benzyne, C6H4, and its cation are of considerable interest in chemistry. Here, the photoion mass-selected threshold photoelectron spectrum of the m-benzyne biradical is presented. An adiabatic ionization energy of 8.65 ± 0.015 eV is derived, while a vibrational progression of 0.10 eV is assigned to the ν9 + ring breathing mode, in excellent agreement with computations. The experimental spectrum was reproduced well by Franck–Condon spectral modeling of the 2A1 ← X 1A1 transition, in which the cation retains a monocyclic C6 framework. The energetically close-lying bicyclic 2A2 cation state exhibits low Franck–Condon factors, due to the large change in geometry, and thus cannot be observed.