Anomalous neutron Compton scattering from molecular hydrogen

Journal Article · Mon Aug 01 04:00:00 EDT 2005 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.72.054123· OSTI ID:20719290

Chatzidimitriou-Dreismann, C A; Krzystyniak, M ^[1]; Abdul-Redah, T ^[2]

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1. Institute of Chemistry, Stranski Laboratory, Technical University of Berlin, D-10623 Berlin (Germany)
2. Physics Laboratory, The University of Kent at Canterbury, Canterbury, Kent CT2 7NR (United Kingdom)

Application of neutron Compton scattering, which operates in the attosecond time scale, to (a) the equimolar H{sub 2}-D{sub 2} mixture and (b) the mixed-isotope system HD (liquids, both at 20 K), reveals a strong anomalous shortfall (about 30%) of the ratio R={sigma}{sub H}/{sigma}{sub D} of H and D cross sections. This striking effect is similar to that observed in liquid H{sub 2}O-D{sub 2}O mixtures [C. A. Chatzidimitriou-Dreismann et al., Phys. Rev. Lett. 79, 2839 (1997)]. Crucially, the shortfall of R is equal in both samples (a) and (b). This result demonstrates that quantum exchange correlations of identical nuclei play no significant role in this effect, thus refuting corresponding theoretical models claiming its interpretation. In contrast, our findings are consistent with alternative theoretical models, in which attosecond dynamics of electronic degrees of freedom (via violation of the Born-Oppenheimer approximation) is considered to participate significantly in the dynamics of an elementary neutron-proton (-deuteron) scattering process. Possible implications for attosecond chemical dynamics, e.g., the onset of bond breaking, are mentioned.

• OSTI ID: 20719290
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 5 Vol. 72; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BORN-OPPENHEIMER APPROXIMATION
COMPTON EFFECT
CORRELATIONS
DEGREES OF FREEDOM
DEUTERONS
ELECTRONS
EXCHANGE INTERACTIONS
HEAVY WATER
HYDROGEN
LIQUIDS
MIXTURES
NEUTRONS
PROTONS
QUANTUM ENTANGLEMENT