The Spectrum of Quasistable States in a Strong Microwave Field

TL;DR

This paper investigates how atoms, specifically lithium, can survive intense microwave pulses by occupying quasistable Rydberg states, revealing spectral patterns and quantum states that explain their resilience.

Contribution

It demonstrates the existence of quasistable Rydberg states in atoms exposed to strong microwave fields and analyzes their spectral signatures and quantum properties.

Findings

Atoms survive in quasistable Rydberg states during intense microwave pulses

Spectra show periodic peaks 38 GHz apart indicating stable energy structures

Quantum calculations support the existence of weakly bound Rydberg orbits

Abstract

When atoms are exposed to intense laser or microwave pulses ~10% of the atoms are found in Rydberg states subsequent to the pulse, even if it is far more intense than required for static field ionization. The optical spectra of the surviving Li atoms in the presence of a 38 GHz microwave field suggest how atoms survive an intense pulse. The spectra exhibit a periodic train of peaks 38 GHz apart. One peak is just below the limit, and with a 90 V/cm field amplitude the train extends from 300 GHz above the limit to 3000 GHz below it. The spectra and quantum mechanical calculations imply that the atoms survive in quasi stable states in which the Rydberg electron is in a weakly bound orbit infrequently returning to the ionic core during the intense pulse.