Glühentladungsspektroskopie

Glühentladung, or glow discharge, is a form of plasma formed when an electric current passes through a gas at low pressure. Energetic electrons ionize and excite the gas, and the subsequent de-excitation emits light. The resulting plasma is typically non-thermal, with electrons much hotter than the bulk gas.

Glow discharges operate at modest voltages and low pressures, with DC, AC, or pulsed power. The light color depends on the gas or gas mixture; neon produces orange-red glows, argon blue or violet, and mercury vapor can yield blue-green light. Phosphor coatings can convert UV emissions to visible light in some lamps.

They are used in signage (neon lamps), fluorescent lighting, and thin-film processing (glow discharge plasmas for sputtering and deposition). Glow discharge spectroscopy is a technique for material analysis. The simplicity and relatively low operating temperature make glow discharges widely studied in plasma physics and applied technologies.

Investigations of glow discharges began in the 19th century, with researchers such as William Crookes documenting luminous regions near electrodes. The term “glow discharge” distinguishes it from spark discharges and helped establish early plasma physics and lighting technologies.