Disentangling the H2E, F(1Σg+) (v′=0-18)←X(1Σg+)(v=3-9)(2+1) REMPI spectrum via 2D velocity-mapped imaging

We have measured the two-photon EF -> X (v '' = 3 - 9) Resonance-Enhanced Multiphoton Ionization (REMPI) spectrum of H-2 by producing the hydrogen molecule via photolysis of H2CO. H-2 is produced with rovibrational energies up to 30,000 cm(-1), at a maximum observed (v '', J '') of (9,5). In the well-resolved jet-cooled H2CO spectrum, ortho and para H-2 are selectively produced with near 100% selectivity. Over 470 REMPI transitions were identified in the EF-X band system, many of which have not been seen previously, including transitions to EF levels not yet accurately measured. Speed distributions were obtained for each REMPI transition using Velocity-mapped imaging, aiding in the assignment by providing a precise measurement of the internal energy of the H-2 molecule.

Automated summary

The study measured the two-photon EF -> X (v '' = 3 - 9) REMPI spectrum of H-2 produced via photolysis of H2CO, with high selectivity for ortho and para H-2. Over 470 REMPI transitions were identified in the EF-X band system, including many previously unseen transitions to EF levels. Speed distributions were obtained for each REMPI transition using Velocity-mapped imaging, aiding in precise measurement of internal energy of H-2 molecule.