The effect of an intense laser field on the binding energy of hydrogenic impurity states with an impurity atom located at the center of a spherical quantum dot confined by an infinite barrier potential are studied as a function of the dot radius and of the intensity and frequency of the laser field.
Angle-resolved mass spectrometry of chloromethanes in an intense laser field
β Scribed by D. Mathur; K. Vijayalakshmi
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 119 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0951-4198
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β¦ Synopsis
Angle-resolved mass spectrometry of tetrachloromethane, trichloromethane and dichloromethane irradiated by intense laser light has been carried out using a quadrupole mass spectrometer. Ionization was by means of very intense, short-duration, linearly polarized laser pulses whose wavelength, pulse duration and intensity were, respectively, 532 nm, 35 ps and 2-8 Γ 10 13 W cm Γ2 . The laser-induced fragmentation pattern was found to be dramatically different from that obtained using conventional mass spectrometric methods with 70 eV electrons. A degree of ion selectivity can be obtained by judicious choice of laser parameters. The direction of the laser's polarization vector with respect to the mass spectrometer's axis is found to be one such important parameter which dramatically affects the morphology of the fragmentation pattern.
π SIMILAR VOLUMES
Laser desorption of neutral molecules followed by electron impact ionization is shown to produce gaseous ion radicals that undergo fragmentation analogous to that observed with electron impact and field ionization. Spectra were measured of heptanal and four deuterium-labeled analogs regenerated from