A theoretical treatment of dissociative recombination (DR), vibrational excitation (VE) and vibrational deexcitation (VdE) of the BeH + ion in its four lowest vibrational states (X 1 Σ + , v + i = 0, 1, 2, 3) is reported. The multichannel quantum defect theory is used to determine cross sections and rate coefficients. Three electronic symmetries of BeH-2 Π, 2 Σ + , and 2 ∆-have been included in the calculations. At low energies the DR is dominated by capture into states of 2 Π symmetry. Satisfactory agreement with results obtained using the wave packet approach is reached at intermediate energies despite significant differences at low energies. Cross sections and rate coefficients suitable for the modeling of the kinetics of BeH + in fusion plasmas and in the stellar atmospheres are presented and discussed.

Abstract.We present MAX-DOAS measurements of NO 2 , HCHO, and aerosols performed in Central Africa, in the city of Bujumbura, Burundi (3.38 Aerosol-extinction and trace-gas vertical profiles are retrieved by applying the optimal-estimation-based profiling tool bePRO to the measured O 4 , NO 2 and HCHO slant-column densities. The MAX-DOAS vertical columns and profiles are used for 5 investigating the diurnal and seasonal cycles of NO 2 , HCHO, and aerosols. Regarding the aerosols, the retrieved AODs are compared to co-located AERONET sun-photometer measurements for verification purposes, while in the case of NO 2 and HCHO, the MAX-DOAS vertical columns and profiles are compared to GOME-2 and OMI satellite observations.To characterise the biomass-burning and biogenic emissions in the Bujumbura region, the trace gases and aerosol MAX-DOAS retrievals are used in combination with MODIS fire radiative-power values and the tropospheric 3D chemical transport 10 model IMAGES, as well as simulations from the NOAA backward-trajectory model HYSPLIT. The first results show that the aerosol and HCHO seasonal variation is driven by the alternation of rain and dry periods, the latter being associated with intense biomass-burning agricultural activities and forest fires in the south/south-east and transport from this region to Bujumbura. In contrast, NO 2 is seen to depend mainly on local emissions close to the city, due to the short lifetime of this species (typically 1-2 hours).

Multichannel quantum defect theory is applied in the treatment of the dissociative recombination and vibrational excitation processes for the BeD + ion in the 24 vibrational levels of its ground electronic state). Three electronic symmetries of BeD ** states ( P 2 , S + 2, and D 2 ) are considered in the calculation of cross sections and the corresponding rate coefficients. The incident electron energy range is 10 −5 -2.7 eV and the electron temperature range is 100-5000K. The vibrational dependence of these collisional processes is highlighted. The resulting data are useful in magnetic confinement fusion edge plasma modeling and spectroscopy, in devices with beryllium based main chamber materials, such as ITER and JET, and operating with the deuteriumtritium fuel mix. An extensive rate coefficients database is presented in graphical form and also by analytic fit functions whose parameters are tabulated in the supplementary material.

We provide cross sections and Maxwell rate coefficients for reactive collisions of slow electrons with BeH + ions on all the eighteen vibrational levels (X 1 Σ + , v + i = 0, 1, 2,. .. , 17) using a Multichannel Quantum Defect Theory (MQDT)-type approach. These data on dissociative recombination, vibrational excitation and vibrational de-excitation are relevant for magnetic confinement fusion edge plasma modelling and spectroscopy, in devices with beryllium based main chamber materials, such as the International Thermonuclear Experimental Reactor (ITER) and the Joint European Torus (JET). Our results are presented in graphical form and as fitted analytical functions, the parameters of which are organized in tables.