Absolute emission probabilities from Photon-excitation Photon-emission (PhexPhem) maps for all H2 singly excited electronic states

• Applicant: Professor Dr. Arno Ehresmann
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas ; Astrophysics and Astronomy
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 512040818

The project “Absolute emission probabilities from PhexPhem maps for all H2 singly excited electronic states” aims at determining complete quantitative experimental data sets for absolute photon absorption and emission probabilities of H2 at room temperature from a quantitative and absolute determination of photon absorption and photon emission cross sections. In emission the full spectral range will be covered relevant to the processes involving all transitions between the singly excited electronic states and the ground state. Measurements will be performed with narrow enough bandwidth of the exciting-photons for rotational resolution in absorption and with rotational resolution in the dispersed emission spectra. More specifically it is intended to dispersively record emitted photons in the wavelength range between 70 and 180 nm and determine from this data absolute emission probabilities after H2 has been excited by narrow bandwidth synchrotron radiation, varied in small steps through the exciting-photon energy range between 11 and 18 eV. All data will be put on a joint and absolute intensity scale. The excitation energy range covers excitation from room temperature populated rotational levels of H_2 X (_^1)Σ(_g)(^+) (v=0) to all known singly excited electronic states. Energies, absorption, and emission probabilities determined from the experiments will be critically compared and benchmarked to existing work such that complete consolidated quantitative experimental data sets will be established. The consolidated data sets will be made available to the astrophysics and plasma physics communities for modelling and data interpretation. The data sets will serve as a basis for a further development of the theoretical models describing these prototype molecule, particularly as only a few separated individual emission intensities have been determined. To the best of my knowledge such complete quantitative experimental and consolidated data sets for all transitions in one experiment do not exist yet.

• DFG Programme: Research Grants