PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Abstract
Interferences in coherent emission of photoelectrons from two
equivalent atomic centers in a molecule are the microscopic analogies
of the celebrated Young’s double-slit experiment. By considering
inner-valence shell ionization in the series of simple hydrocarbons
C2H2, C2H4, and C2H6, we show that double-slit interference is widespread
and has built-in quantitative information on geometry, orbital
composition, and many-body effects. A theoretical and experimental
study is presented over the photon energy range of 70–700 eV. A
strong dependence of the oscillation period on the C–C distance is
observed, which can be used to determine bond lengths between
selected pairs of equivalent atoms with an accuracy of at least 0.01 Å.
Furthermore, we show that the observed oscillations are directly informative
of the nature and atomic composition of the inner-valence
molecular orbitals and that observed ratios are quantitative measures
of elusive many-body effects. The technique and analysis can be
immediately extended to a large class of compounds.
