Document Type

Article

Publication Date

5-2002

Publication Title

Physical review letters

Publisher

American Physical Society

Volume

88

Issue

20

First page number:

203002-1

Last page number:

203002-4

Abstract

We have observed photoexcitation of the dipole-forbidden 1s21S0→2p21D2 resonance in helium by measuring the nondipolar forward-backward asymmetry of photoelectron angular distributions in the 2ℓ2ℓ autoionizing region. By exploiting the electric dipole-quadrupole interference in the excitation of both the 2s2p1P1 and 2p21D2 levels, we have observed the quadrupole resonance in photoabsorption and extracted its Fano line shape parameters and the relative phase of the 1sEp and 1sEd continua. We find the quadrupole line profile index q2 to be markedly different from theoretical expectations.

Keywords

Angular distribution (Nuclear physics); Conduction electrons; Dipole moments; Photoionization

Disciplines

Atomic, Molecular and Optical Physics | Inorganic Chemistry | Nuclear | Physical Chemistry

Language

English

Permissions

Copyright American Physical Society. Used with permission.

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