Shape resonances in H${}_2$ as photolysis reaction intermediates

Abstract

Shape resonances in H${}_2$, produced as reaction intermediates in the photolysis of H${}_2$S precursor molecules, are measured in a half-collision approach. Before desintegrating into two ground state H atoms, the reaction is quenched by two-photon Doppler-free excitation to the F electronically excited state of H${}_2$. For $J=13,15,17,19$ and 21, resonances with lifetimes in the range of nano to milliseconds were observed with an accuracy of 30~MHz (1.4~mK). The experimental resonance positions are found to be in excellent agreement with theoretical predictions when nonadiabatic and quantum electrodynamical corrections are included. This is the first time such effects are observed in collisions between neutral atoms. From the potential energy curve of the H${}_2$ molecule, now tested at high accuracy over a wide range of internuclear separations, the s-wave scattering length for singlet H(1s)+H(1s) scattering is determined at $a=0.2735_{31}^{39}{a}_0$.

5 Pages, 4 Figures, Accepted by Phys. Rev. Lett

References in corpus (5)

• Tuning the scattering length with an optically induced Feshbach resonance
• Molecule formation in ultracold atomic gases
• Benchmarking theory with an improved measurement of the ionization and dissociation energies of H${}_2$
• Observation and calculation of the quasi-bound rovibrational levels of the electronic ground state of H${}_2^{+}$
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Cited by in corpus (2)

• Spectroscopic study of the F${}^1{\Sigma }_g^{+}$ outer well state in H${}_2$, HD and D${}_2$
• The quasi bound spectrum of H2