A scheme of matrix ionization in UV matrix-assisted laser desorptiodionization is presented. Excitation to an upper lying electronic singlet state by the absorption of two photons and subsequent thermionic emission by vibronic coupling is proposed as the primary route for the formation of unprotonat
Ultraviolet laser induced ionization of molecules near surfaces
โ Scribed by Richard B. Opsal; James P. Reilly
- Publisher
- Elsevier Science
- Year
- 1983
- Tongue
- English
- Weight
- 426 KB
- Volume
- 99
- Category
- Article
- ISSN
- 0009-2614
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โฆ Synopsis
Aromatic molecules are multiphoton ionized in the source region of a time-of-flight mass spectrometer using the output from a KS escimer laser. Under certain operating conditions unusnally sharp mass spectral peaks are observed. It is demonstrated that these result from ionization of molecules initially adsorbed to a metal surface. The implications of this phenomenon are briefly discussed.
๐ SIMILAR VOLUMES
The observed structure in the ionization cross section just above the threshold has been attributed to the formation of auto-ion'zing Rydberg states. The calculation of the auto-ionization rates is discussed in terms of the breakdown rf the Born-Oppenheimer approximation. Three aspects are examined
The ionization mechanisms in matrix-assisted laser desorption/ionization (MALDI) remain poorly understood. We have begun a program of study aimed at determining the properties of matrix molecules which make them suitable for MALDI. Initial results are presented here for one of the most widely used m
## Abstract Film samples of two very pure polyolefins, lowโdensity polyethylene (LDPE) and biaxially oriented polypropylene (BOPP), were surfaceโmodified by vacuum ultraviolet (VUV) photochemistry in lowโpressure ammonia. The influence of experimental conditions such as wavelength and intensity (ph