Fragmentation and reliable size distributions of large ammonia and water clusters

Bobbert, C.; Schütte, S.; Steinbach, C.; Buck, U.

doi:10.1140/epjd/e20020070

Cited by 72 publications

(144 citation statements)

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“…6,26,27 We obtained mean cluster sizes of N = 58 for the 40 eV data set, and N = 84 for both 60 eV data set (more details are available in the supplementary material 28 ). For the 40 eV data set, the nozzle temperature had to be estimated from the heating power, instead of a thermocouple reading.…”

Section: Methodsmentioning

confidence: 99%

The photoelectron angular distribution of water clusters

Zhang

Andersson

Förstel

et al. 2013

The Journal of Chemical Physics

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The angular distribution of photoelectrons emitted from water clusters has been measured by linearly polarized synchrotron radiation of 40 and 60 eV photon energy. Results are given for the three outermost valence orbitals. The emission patterns are found more isotropic than for isolated molecules. While a simple scattering model is able to explain most of the deviation from molecular behavior, some of our data also suggest an intrinsic change of the angular distribution parameter. The angular distribution function was mapped by rotating the axis of linear polarization of the synchrotron radiation. [http://dx

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Section: Methodsmentioning

confidence: 99%

The photoelectron angular distribution of water clusters

Zhang

Andersson

Förstel

et al. 2013

The Journal of Chemical Physics

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“…3 ) several other methods have been developed, e.g., electron diffraction, [29][30][31][32] cluster beam scattering by a buffer gas, 33 pickup of sodium atoms and photoionization, 34 and helium atom diffraction on clusters. 35 Here we are concerned with two methods for the mean cluster size determination using the pickup process: (1) The first method consists in measuring the variations of the average beam velocity with the pickup pressure.…”

Section: Introductionmentioning

confidence: 99%

Cluster cross sections from pickup measurements: Are the established methods consistent?

Fedor

Poterya

Pysanenko

et al. 2011

The Journal of Chemical Physics

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Pickup of several molecules, H 2 O, HBr, and CH 3 OH, and Ar atoms on free Ar N clusters has been investigated in a molecular beam experiment. The pickup cross sections of the clusters with known mean sizes,N ≈ 150 and 260 were measured by two independent methods: (i) the cluster beam velocity decrease due to the momentum transfer of the picked up molecules to the clusters, and (ii) Poisson distribution of a selected cluster fragment ion as a function of the pickup pressure. In addition, the pickup cross sections were calculated using molecular dynamics and Monte Carlo simulations. The simulations support the results of the velocity measurements. On the other hand, the Poisson distributions yield significantly smaller cross sections, inconsistent with the known Ar N cluster sizes. These results are discussed in terms of: (i) an incomplete coagulation of guest molecules on the argon clusters when two or more molecules are picked up; and (ii) the fragmentation pattern of the embedded molecules and their clusters upon ionization on the Ar cluster. We conclude that the Poisson distribution method has to be cautiously examined, if conclusions should be drawn about the cluster cross section, or the mean cluster sizeN , and the number of picked up molecules.

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“…The clusters were generated in a molecular beam machine with a reflectron time-of-flight ͑RETOF͒ mass spectrometer being described elsewhere in detail. 18,19 A water cluster beam is skimmed and crosses an atmosphere of sodium vapor created in a pickup cell ͑cell temperature of 490 K͒. The sodium doped clusters are detected by photoionization, mass resolved in the RETOF, and the ions are recorded by a multichannel plate.…”

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confidence: 99%

“…This setup is particularly capable of generating molecular beams with high abundances of large clusters. 18,19 Expanding pure water at a stagnation pressure of 6.5 bar ͑reservoir temperature of 430 K and nozzle temperature of 440 K͒, a cluster size distribution with a median of ͗n͘ = 300 is generated. The upper panel of Fig.…”

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confidence: 99%