Photoionization of the primary photofragments of chlorine dioxide (OClO) and dichlorine monoxide is (Cl 2 O) reported. The nascent photofragments are formed by UV photolysis, they are subsequently photoionized by time-correlated XUV laser radiation and Ðnally detected by time-of-Ñight mass spectrometry. Primary photolysis of OClO leads to the formation of ClO ] O at j \ 359.5 nm, whereas ClO ] Cl are formed by photolysis of at j \ 250 nm. The XUV photoionization of the photolysis products relies on single Cl 2 O photon ionization. This allows to derive partial photoionization cross sections of the parent cations and their photolysis products from mass spectral intensities by using the absolute photoionization cross sections of the atomic products for calibration. SpeciÐcally, we obtain for OClO at E \ 13.74 eV : Mb and p ClO \ 27 ^5 Mb. Consistent Ðndings are obtained from equivalent experiments on The present p OClO \ 18.5 ^3 C l 2 O. results are compared with previous photoionization work on ClO and OClO to demonstrate the reliability of UV-pump/XUV-probe spectroscopy.

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An experimental device is reported that utilizes time-correlated nanosecond light pulses in combination with photoionization mass spectrometry. A primary light pulse is generated by a tunable dye laser in the ultraviolet regime, which photolyzes neutral gas targets under collision free conditions. Subsequently, a time-correlated extreme ultraviolet-light pulse comes from a laser-produced plasma that is monochromatized in the 10–25 eV regime. The photolysis products are ionized by one-photon absorption, so that the cations are finally detected by time-of-flight mass spectrometry. The performance of this experimental approach is characterized by investigating the primary photolysis products of chlorine dioxide. Finally, possible applications of this approach are briefly discussed.

Abstract-A laser-desorption mass spectrometer will be part of the ESA-led ExoMars mission with the objective of identifying organic molecules on planet Mars. A UV laser source emitting nanosecond pulses with pulse energy of about 250 μJ at a wavelength of 266 nm is required for the ionization of nonvolatile soil constituents. A passively q-switched, diode-pumped Nd:YAG laser oscillator with external frequency quadrupling has been developed. The basic optical concept and a previously developed flight-near prototype are redesigned for the engineering qualification model of the laser, mainly due to requirements updated during the development process and necessary system adaptations. Performance issues like pulse energy stability, pulse energy adjustment, and burst mode operation are presented in this paper.

the MOMA laser team a,b a Laser Zentrum Hannover e.V., ABSTRACT A space-qualified flight model of a pulsed ultraviolet (UV) laser has been developed for the Mars Organic Molecule Analyzer (MOMA) instrument of the ExoMars 2020 mission. The design is based on a passively Q-switched Nd:Cr:YAG laser oscillator with subsequent two-stage frequency quadrupling. It emits nanosecond pulses with an energy tuneable between 13 µJ and 130 µJ at a wavelength of 266 nm.Considering its small physical dimensions and weight, the interior of the laser head is rather complex. Besides the aforementioned infrared oscillator and frequency conversion stage it contains the pump optics, two wavelength division assemblies within main beam path, a complex monitoring stage including two photodiodes for pulse energy measurement, a beam shaping setup and a deflection unit for fine adjustment of the beam pointing towards the sample location within the instrument. Most of the laser head is enclosed in a hermetically sealed housing, while the deflection unit is sealed separately. Both volumes are filled with 1 bar of dry, filtered air.