Momentum vector correlations in three-particle fragmentation of triatomic hydrogen

Abstract

The correlation pattern in the center of mass motion of the three fragments from dissociation of well-defined Rydberg states of H 3 and D 3 is studied. Dissociation of the molecules is induced by an external electric field. Through a comparison with results obtained in radiative cascading we can show that the correlation pattern is that of the short-lived 2s 2 A 1 electronic state, of which a tiny amplitude is admixed by the external electric field. A comparison of our results with the predictions by M. Lehner and M. Jungen [J. Phys. B 42, 065101 (2009)] and U. Galster [Phys. Rev. A 81, 032517 (2010)] for predissociation of the 2s 2 A 1 state is made. We show that the experimental vector correlation maps are direct images of the spatial symmetry of the product of the vibrational wave function and spatial dependence of the nonadiabatic coupling operator.

Three-body predissociation of D3and H332A′(2sa′1): wave packet dynamics and momentum correlation

“…In the upper row of Dalitz plots, the underlying vibrational wavefunctions are totally symmetrical (A 1 ), whereas the lower row of diagrams is linked to degenerate (E ) vibrational modes. Compared to experiment [14,15] our computed momentum distributions generally show finer structures, which might be a consequence of our restriction to J = 0. The inclusion of higher rotational quantum numbers would presumably tend to smooth out the peaks.…”

“…The results of momentum correlation measurement [10][11][12][13][14][15] for the three-particle dissociation of H 3 and D 3 may by represented as beautifully structured 'Dalitz plots' [16]. The details of these momentum correlation diagrams depend on the initial electronic state and the corresponding rovibrational quantum numbers and also on the nonadiabatic transition to the coupled ground state potential energy surfaces (PES).…”

Profound Isotope Effect in Dissociation of Triatomic Hydrogen

“…These peaks are also enhanced by the presence of an electric field. This signal arises from field-induced mixing of the long-lived 2p 2 A 2 ″ state (in various forms of vibrational excitation) with the rapidly predissociated 2s 2 A′ 1 state. , In addition, weaker contributions appear at energies of the 2s levels. These are due to radiative decay of higher lying long-lived Rydberg states.…”

“…This signal arises from field-induced mixing of the long-lived 2p 2 A 2 ″ state (in various forms of vibrational excitation) with the rapidly predissociated 2s 2 A′ 1 state. 17,18 In addition, weaker contributions appear at energies of the 2s levels. These are due to In other words, the bending mode excited contribution in D 3 amounts to ≈60% whereas it is only ≈4% in H 3 .…”

“…In the 3 mm long shielded Stark-field region an inhomogeneous dc electric field of up to E = 42 kV/cm can be generated by two razor blade electrodes spaced by 2 mm. The electric field induces dissociation of some of the neutral molecules by Stark-mixing with short-lived molecular states. ,, Dissociation fragments with sufficiently high transverse momentum pass the beam flag and reach the multihit coincidence detector after a free flight of variable length, ranging from L = 1150 to 2450 mm. Atomic fragments from a dissociated molecule are detected in triple coincidence on a planar multihit detector with a spatial resolution of 60 μm and a temporal resolution of 25 ps.…”