Learn More
Here we report the first mass spectrometric study of negative ions formed via free electron attachment (EA) to nucleobases (NBs) embedded in helium clusters. Pure and mixed clusters of adenine and thymine have been formed by pickup of isolated NB molecules by cold helium droplets. In contrast to EA of isolated molecules in the gas phase we observe a(More)
Attachment of free electrons to water clusters embedded in helium droplets leads to water-cluster anions (H2O)n(-) and (D2O)n(-) of size n > or = 2. Small water-cluster anions bind to up to 10 helium atoms, providing compelling evidence for the low temperature of these complexes, but the most abundant species are bare cluster anions. In contrast to previous(More)
The dissociative electron attachment to the gas phase nucleobase adenine is studied using two different experiments. A double focusing sector field mass spectrometer is utilized for measurements requiring high mass resolution, high sensitivity, and relative ion yields for all the fragment anions and a hemispherical electron monochromator instrument for high(More)
The inelastic electron interaction (ionization/attachment) with chloroform embedded in helium droplets has been studied utilizing a two-sector field mass spectrometer. Positive mass spectra have been recorded at the electron energy of 70 eV and are compared with previous results in the gas phase and with other systems embedded in helium droplets. Moreover,(More)
—A monolithic circuit has been designed for active quenching and active-reset of single-photon avalanche diodes (SPADs), which operate above the breakdown voltage BD for detecting single photons. To the best of our knowledge, this is the first fully integrated circuit of this kind ever reported. It can operate with any available SPAD device, since it(More)
Surface-induced interactions of the projectile ion C(2)D(4)(+) with room-temperature (hydrocarbon covered) stainless steel, carbon highly oriented pyrolytic graphite (HOPG), and two different types of diamond surfaces (O-terminated and H-terminated) were investigated over the range of incident energies from a few eV up to 50 eV. The relative abundance of(More)
Fragmentation of metastable SF(6)(-*) ions formed in low energy electron attachment to SF(6) has been investigated. The dissociation reaction SF(6)(-*)-->SF(5) (-)+F has been observed approximately 1.5-3.4 micros and approximately 17-32 micros after electron attachment in a time-of-flight and a double focusing two sector field mass spectrometer,(More)
Water clusters are known to undergo an autoprotonation reaction upon ionization by photons or electron impact, resulting in the formation of (H(2)O)(n)H(3)O(+). Ejection of OH cannot be quenched by near-threshold ionization; it is only partly quenched when clusters are complexed with inert gas atoms. Mass spectra recorded by electron ionization of(More)