Lyman-alpha emission via resonant energy transfer

Abstract

Very intense hydrogen Lyman-α (2p 2 P 0 → 1s 2 S) light emission (λ = 121.6 nm) is observed from neon gas near atmospheric pressure containing small admixtures (per mil) of hydrogen when this gas mixture is excited by ionizing particle beams. A DC beam of 15 keV electrons or a pulsed beam of 100 MeV 32 S ions were used in different experiments for excitation. A collisional energy transfer rate constant from neon to H * of (3±1)×10 −11 cm 3 s −1 has been measured using time-resolved optical spectroscopy on the Lyman-α line. Conversion efficiencies of particle beam power into Lyman-α light of the order of 10% have been observed. No other significant radiation was emitted in the entire VUV, UV and visible spectral region. In particular, no other hydrogen lines are observed under these conditions. The selective excitation of the H(2p) level is interpreted as arising from a resonant energy transfer between Ne * 2 excimers and hydrogen molecules.

Laser-Induced Acoustic Desorption Atmospheric Pressure Photoionization via VUV-Generating Microplasmas

“…For the operating conditions described, Lyman-α flux was found to be greatest at a discharge current of 10 mA, which corresponds to an applied voltage of -1130 V. Though Lyman-α emission from MHCDs is known, it was important to assess generation and transmission through the LiF window for our particular device. Previous reports of these devices typically have them operating at pressures below 1 atm [20,24,25]. This demonstrates that Lyman-α can be successfully generated in the relatively high-pressure environment of our device and transmitted through the LiF window for photoionization use.…”

Resonant energy transfer from argon dimers to atomic oxygen in microhollow cathode discharges

“…5 The energy of the excited neon atom, or neon dimer is sufficient to dissociate hydrogen and to excite the hydrogen atom to a state, which decays by emitting hydrogen Lyman-␣ and Lyman-␤ radiation at 121.6 and 102.5 nm, respectively. 3 This effect proved to be very efficient, and generates a radiation, which due to its short wavelength, and small spectral width ͑compared to excimer emission͒ is considered to be a good candidate for advanced vacuum-ultraviolet ͑VUV͒ photolithography.…”

An ultracompact photo-ionization time-of-flight mass spectrometer with a novel vacuum ultraviolet light source for on-line detection of organic trace compounds and as a detector for gas chromatography

“…The novel EBEL lamp system has been described in some recent publications [11][12][13][14][15][16] and therefore is only briefl y described here (Fig. 1).…”

“…The EBEL lamp system was developed at the Technical University, Munich. [11][12][13] Currently, at GSF, homebuilt VUV EBEL lamps are being used (Fig. 2).…”

“…[11][12][13] The practicability of the EBEL light source for single-photon ionization mass spectrometry (SPI-MS) was fi rstly demonstrated in 2001. 14 Subsequently, prototypes of EBEL-based SPI-MS systems based on the quadrupole mass spectrometer (QMS) 15 and an improved time-of-fl ight mass spectrometer (TOFMS) 16 have been developed and tested.…”