title: A pulsed uniform Laval expansion coupled with single photon ionization and mass spectrometric detection for the study of large molecular aggregates.
abstract: We report on a new instrument that allows for the investigation of weakly-bound molecular aggregates under equilibrium conditions (constant temperature and pressure). The aggregates are formed in a Laval nozzle and probed with time-of-flight mass spectrometry in the uniform postnozzle flow; i.e. in the equilibrium region of the flow. Aggregates over a very broad size range from the monomer to particle sizes of 10-20 nm can be generated and studied with this setup. Soft ionization of the aggregates is performed with single photons from a homemade vacuum ultraviolet laser. The mass spectrometric detection provides molecular-level information on the size and chemical composition of the aggregates. This new instrument is useful for a broad range of cluster studies that require well-defined conditions.
authors: ETH Zürich, Laboratory of Physical Chemistry, Vladimir-Prelog-Weg 2, CH-8093, Zürich, Switzerland. rsignorell@ethz.ch.
authors: Bernhard
authors: B
authors: Schläppi
authors: Jessica H
authors: JH
authors: Litman
authors: Jorge J
authors: JJ
authors: Ferreiro
authors: David
authors: D
authors: Stapfer
authors: Ruth
authors: R
authors: Signorell