Optical emission spectroscopy in which a radiofrequency-powered
glow discharge is operated with frequencies in the low megahertz range.
Note:
The use of these frequencies establishes a negative direct current (DC)-bias voltage on the sample surface. The DC-bias is the result of an alternating current waveform that is centered about negative potential; as such it more or less represents the average potential residing on the sample surface. Radio-frequency has ability to appear to flow through insulators (non-conductive materials).
Source:
PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 731 (https://doi.org/10.1515/pac-2019-0203)