Cross sections and modelling results for TGF- and positron spectrum produced by a negative stepped lightning leader

We model the energy resolved angular distribution of TGFs and of positrons produced by a negative lightning leader stepping upwards in a thundercloud. First we present our new results for doubly differential cross sections for Bremsstrahlung and pair production based on the triply differential cross-sections of Bethe and Heitler. Other cross sections in literature and databases do not cover the appropriate energy range or do not apply to the small atomic numbers of nitrogen and oxygen or do not resolve both energies and emission angles of emitted photons or positrons. Second we have extended the Monte Carlo model of Chao Li towards relativistic electron energies, and we have included the new cross sections as well as Compton scattering of photons and photo ionization. We will present the angular resolved spectrum of TGFs and positrons of stepped negative leaders and compare it with results of other authors

Bis(trimethyl­ammonium) tetra­chlorido­diphenyl­stannate(IV)

The title compound, [(CH3)3NH]2[Sn(C6H5)2Cl4], consists of [(CH3)3NH]+ cations and [SnPh2Cl4]2− anions in which the Sn atom, located on a centre of inversion, is bonded to four Cl atoms and two phenyl rings, giving an octa­hedral geometry with the phenyl rings in trans positions. In the crystal, the cations and the anions are connected by N—H⋯Cl hydrogen bonds and C—H⋯Cl inter­actions

Dibenzyl­aza­nium (oxalato-κ2 O,O′)triphenyl­stannate(IV)

The title compound, (C14H16N)[Sn(C6H5)3(C2O2)], was synthesised by allowing C2O4(Bz2NH2)2 (Bz = benzyl) to react with SnPh3Cl. The asymmetric unit is built up by four SnPh3C2O4 anions and four Bz2NH2 cations which are related by a pseudo-inversion centre. Each SnIV cation is five-coordinated by the three phenyl groups and two O atoms belonging to the chelating oxalate ligand; the coordination geometry is that of a distorted trigonal bipyramid. Anions and cations are linked through N—H⋯O hydrogen bonds into a layer structure parallel to (001). Moreover, the anion–cation pairs are associated by two bifurcated N—H⋯O hydrogen bonds, generating pseudo-dimers. One of the phenyl groups of one anion is disordered over two sets of sites in a 0.69:0.31 ratio. The Flack parameter value of 0.44 (1) indicates racemic twinning