title: Anisotropic x-ray emission from heliumlike Fe24+ ions aligned by resonant coherent excitation with a periodic crystal potential.
abstract: We have measured deexcitation x rays emitted from the resonant coherently excited 2(1)P(1) state of heliumlike Fe24+ ions of 423 MeV/amu, planar channeling through a Si crystal. Large anisotropy in the angular distribution of deexcitation x-ray emission is observed: the x-ray emission in the direction parallel to the channeling plane is favored by a factor of 2 compared to the perpendicular direction. This anisotropy originates from the direction of the periodic crystal field, which populates specific m states in resonant coherent excitation and aligns the excited states.
authors.affiliation: Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Azuma
authors.forename: Y
authors.initials: Y
authors.lastname: Takabayashi
authors.forename: C
authors.initials: C
authors.lastname: Kondo
authors.forename: T
authors.initials: T
authors.lastname: Muranaka
authors.forename: K
authors.initials: K
authors.lastname: Komaki
authors.forename: Y
authors.initials: Y
authors.lastname: Yamazaki
authors.forename: E
authors.initials: E
authors.lastname: Takada
authors.forename: T
authors.initials: T
authors.lastname: Murakami