In a crossed laser-atomic-beam experiment, eight neon transitions between the levels 1s and 2p are measured to an accuracy of 3–4 parts in 1010 by a direct comparison with a standard laser from the National Bureau of Standards. These transitions are 1s5 → 2p7, 1s3 → 2p5, 1s5 → 2p8, and 1s3 → 2p7 from both 20Ne and 22Ne. The isotope shifts of these transitions are determined to an accuracy of 0.1 MHz.
© 1987 Optical Society of America
Ping Zhao, "High-precision measurement of 20Ne and 22Ne transitions," J. Opt. Soc. Am. B 4, 644-647 (1987)