Lyman-α, Lyman-α coincidence detection in the photodissociation of doubly excited molecular hydrogen into two H(2p) atoms

Abstract

Photodissociation processes of the doubly excited states of H2 into H(2p)+H(2p) have been studied using a coincidence detection of two Lyman-α photons. Coincidence spectra have been measured in the energy region of 29.0–36.0 eV. The intensity of the observed coincidence peak corresponding to two Lyman-α photons increases with increasing energy from its threshold which is about 29 eV. The main precursor of the two H(2p) atoms is assigned to the doubly excited Q2 1Πu state.

Tunneling and decay dynamics of H̄ 1Σg+ outer well states in hydrogen

“…Dissociative decay was investigated by monitoring Lyman and Balmer emission from the atomic H-fragments in excited states, 2,3 even in coincidence when two excited H-atoms were produced. 4 Decay by autoionization was detected with angular and kineticenergy resolution. 5 In these studies super-excited states of u symmetry were probed, however, limited to the FranckCondon region, i.e., states which have vibrational wave functions that overlap with the X 1 ⌺ g ϩ , vϭ0 ground state, located in a narrow region of internuclear distance.…”

Formation of metastable atomic hydrogen in the 2sstate from symmetry-resolved doubly excited states of molecular hydrogen

“…However, the excitation spectrum of Ref. [22] does not agree with the recent one by Odagiri et al [23], the latter of which is more reliable [23]. Odagiri et al [23] found that the precursor doubly excited state for the formation of two H(2p) atoms is the Q 2 1 u (1) state, which disagrees with the argument above.…”

“…On the other hand, the Q 2 1 u (2) state was concluded to dissociate into H(2p) + H(2p) because the excitation spectrum of the simultaneous emission of two Lyman-α photons in photoexcitation of H 2 [22] were well reproduced by the calculated photoabsorption or photodissociation profiles due to the Q 2 1 u (2) state [4,19]. However, the excitation spectrum of Ref.…”

Quantum-Mechanical Definition of Atoms and Chemical Bonds in Molecules

“…Such latter results, even in the simple case of symmetric collinear triatomic hydrogen reported here, are seen to be significantly more complex than the better-known cases of the entangled limits of homo-nuclear diatomic molecules [80,81]. Since adiabatic dissociation of coherent molecular electronic states can be achieved experimentally in various ways under appropriate conditions [82][83][84][85][86][87][88][89], an ensemble of measurements of the entangled electronic energies of atomic fragments produced by the dissociation of polyatomic molecules can potentially report distributions of these for comparisons with theoretical predictions.…”