Ionization of Na Rydberg atoms by a 79-GHz microwave field

Journal Article · Thu Nov 17 00:00:00 EST 2016 · Physical Review A

DOI:https://doi.org/10.1103/physreva.94.053416· OSTI ID:1535716

Arakelyan, A. ^[1]; Nunkaew, J. ^[2]; Gallagher, T. F. ^[3]

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1. Univ. of Virginia, Charlottesville, VA (United States); Univ. of Michigan, Ann Arbor, MI (United States)
2. Chiang Mai Univ. (Thailand)
3. Univ. of Virginia, Charlottesville, VA (United States)

In this work, we have measured the ionization fields for Na Rydberg states of $n\ge 26$ by a 79-GHz microwave field. At low $n$, where the microwave frequency $\omega$ is one-third the classical Kepler frequency ${\omega }_K$, which is equal to the $1/n^3$ spacing between $n$ states, the ionization field is $\approx 1/3n^5$, in atomic units. As $n$ is raised ${\omega }_K$ decreases, and the ionization field rises above $1/3n^5$, reaching a constant value when $\omega ={\omega }_K$. At very high $n$, where $\omega >1/2n^2$, single photoionization is possible, and the measured rate agrees with the calculated value. These measurements, together with those done previously, connect the processes of field ionization and photoionization in Na. At low $n$ and radio frequencies ionization is simply field ionization, and at very high $n$ it occurs by photoionization, single-photon absorption. These measurements also show that microwave ionization of Rydberg atoms at 79 GHz results in significant populations' being left in the very high-lying states.

• Research Organization: Univ. of Virginia, Charlottesville, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: FG02-97ER14786; 030/2557
• OSTI ID: 1535716
• Alternate ID(s): OSTI ID: 1332592
• Journal Information: Physical Review A, Vol. 94, Issue 5; ISSN 2469-9926
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
atomic & molecular processes in external fields
multiphoton or tunneling ionization & excitation
single- and few-photon ionization & excitation
atomic & molecular beams
Rydberg atoms & molecules