2024/08/22 by Moto Togawa, Steffen Kühn, Togawa, Moto +25 · 1 citation
Chemistry · Physics and Astronomy · #Atomic Physics (physics.atom-ph) #Atomic and Molecular Physics #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Mass Spectrometry Techniques and Applications
paper · pdf · doi:10.48550/arxiv.2408.12219
openalex publication_date 2024/08/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The transition energies of the two 1s-core-excited soft X-ray lines (dubbed q and r) from 1s2 2s 1S1/2 to the respective upper levels 1s(2S)2s2p(3P) 2P3/2 and 2P1/2 of Li-like oxygen, fluorine and neon were measured and calibrated using several nearby transitions of He-like ions. The major remaining source of energy uncertainties in monochromators, the periodic fluctuations produced by imperfect angular encoder calibration, is addressed by a simultaneously running photoelectron spectroscopy measurement. This leads to an improved energy determination of 5 parts per million, showing fair agreement with previous theories as well as with our own, involving a complete treatment of the autoionizing states studied here. Our experimental results translate to an uncertainty of only 1.6 km/s for the oxygen line qr-blend used to determine the outflow velocities of active galactic nuclei, ten times smaller than previously possible.