Energy and angular distributions of electrons from sodium atoms photo-ionized with femtosecond laser pulses

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Tarih

2021

Dergi Başlığı

Dergi ISSN

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Yayıncı

IOP Publishing Ltd

Erişim Hakkı

info:eu-repo/semantics/closedAccess

Özet

We studied photoelectron angular distributions (PADs) and energy spectra of sodium atoms photo-ionized with intense short laser pulses in the near-infrared region. Energy spectra of photoelectrons due to multistep ionization of sodium atoms through intermediate levels 5p, 6p, 7p, and 4f were observed in above threshold ionization (ATI) at laser intensities of 2 × 1013 W cm−2 and 1 × 1013 W cm−2. The PADs from the 5p(4f) state for zero, first, second and third order ATI peaks were measured. We observed that for the two selected laser intensities the angular distribution of photoelectrons showed only slight variations. The PADs exhibit main lobes within ∼60◦ degrees from the laser polarization and additional lobes that become more pronounced with the increasing ATI peak number. Besides a general analytical representation of the observed angular dependences, the experimental PADs for each ATI peak were fitted with Legendre polynomials accounting for different ionization channels. The good agreement between the experimental data and fitting functions allowed to evaluate the contributions of the ionization channels to the observed ATI orders. The calculations of the photoelectron spectra by numerically solving the time-dependent Schrödinger equation in a single active electron approximation produced agreement with the experiment in the main features of the spectra, while differences in more subtle details were observed.

Açıklama

Anahtar Kelimeler

Above threshold ionization, Angular distributions, Photoelectron

Kaynak

Journal of Physics B: Atomic, Molecular and Optical Physics

WoS Q Değeri

Q3

Scopus Q Değeri

Cilt

54

Sayı

14

Künye

Boran, Y., Hart, N., Kaya, N., Zhou, J., Kolomenskii, A. A., & Schuessler, H. A. (2021). Energy and angular distributions of electrons from sodium atoms photo-ionized with femtosecond laser pulses. Journal of Physics B: Atomic, Molecular and Optical Physics, 54(14) doi:10.1088/1361-6455/ac0c29