Quantum evaporation of4He

✍ Scribed by A. F. G. Wyatt

• Publisher: Springer US
• Year: 1992
• Tongue: English
• Weight: 786 KB
• Volume: 87
• Category: Article
• ISSN: 0022-2291
• DOI: 10.1007/bf00114914

✦ Synopsis

Quantum evaporation is the process in which an excitation is annihilated at the free surface and an atom is ejected. With liquid 4He the excitation is a phonon or a R § or R-roton. The conditions necessary to observe this phenomenon are discussed and the various experiments that demonstrate the conservation of energy and parallel component of momentum are reviewed. It is shown that phonons, with energy >1OK, and rotons have long lifetimes, tending to ~ as T ~ O. These excitations can be injected into liquid He and collimated into beams so that angular and scattering measurements can be performed.