Transferring pharmaceuticals into the gas phase

Christen, Wolfgang; Krause, Tim; Rademann, Klaus

doi:10.1016/j.ijms.2008.04.029

Cited by 9 publications

(8 citation statements)

References 22 publications

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“…The advantage of this particular technique is that the target composition, that is, the size of the droplets and of the embedded metal clusters can be adjusted independently by varying the rare gas backing pressure and the metal partial pressure in the pick-up cell. The method can be extended to other rare gases and even molecular species and allows for experiments on nanosolvents directly in the gas phase. , As other possible applications, metal cluster soft-landing and cluster-surface scattering experiments are conceivable. Resonant two-photon ionization on the embedded complexes has proven that optical properties of embedded metal clusters can be probed.…”

Section: Discussionmentioning

confidence: 99%

Argon Solvent Effects on Optical Properties of Silver Metal Clusters

et al. 2011

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Argon gas at a high pressure (∼80 bar) has been expanded using a miniaturized pulsed valve at room temperature, producing a supersonic beam of cold, large argon droplets. Atoms of silver are subsequently embedded into the droplet using the pick-up technique. The resulting Ag n Ardroplet distribution was analyzed using multiphoton laser ionization time-of-flight mass spectrometry. Besides bare metal clusters, snowballs of silver monomers and dimers encapsulated in up to 50 argon atoms have been observed. The influence of the solvent on the optical absorption of the solute was studied for embedded Ag8 using resonant two-photon ionization in the ultraviolet. A redshift and broadening of the Ag8Ardroplet optical spectrum compared to that measured in pure [Federmann et al., Eur. Phys. J. D 1999, 9, 11] and Ar-doped helium droplets [Diederich et al., J. Chem. Phys. 2002, 116, 3263] was observed, which is attributed to the interaction with the larger Ar matrix environment.

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Section: Discussionmentioning

confidence: 99%

Argon Solvent Effects on Optical Properties of Silver Metal Clusters

et al. 2011

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“…Deviations at pressures P 0 > 0 thus can be ascribed to illegitimate model assumptions. This is further illustrated in (9), resembling the ideal gas description at zero pressure. This scenario thus represents no cluster formation in the beam.…”

Section: Numerical Resultsmentioning

confidence: 80%

Probing free jet expansions of supercritical fluids

Christen¹,

Rademann

2009

Phys. Scr.

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Attempting to improve the comprehension of supersonic molecular beams at elevated pressures we present a comparative study of thermodynamic descriptions of the terminal flow velocity in free jet expansions. As model system we choose carbon dioxide due to its widespread utilization in supercritical fluid technology. Numerical results for the thermodynamic quantities are obtained using a high accuracy equation of state explicit in the Helmholtz free energy. The influence of pressure and temperature on the beam velocity is investigated for a broad range of stagnation conditions. A consistent physical picture is obtained for calculations employing the initial and final molar enthalpies, while enormous discrepancies are found for descriptions based on the molar isobaric heat capacity or the heat capacity ratio. The deviations are particularly pronounced at the gas-liquid phase transition and in the vicinity of the critical point and can be related to the diverse assumptions of ideal gas behavior. It is shown that computations using real fluid enthalpies permit to assess the fraction of condensation in supersonic jets.

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“…[83][84][85][86] One of the numerous interesting questions in this context is the fate of the condensation energy that is released during cluster formation, which may show up in an increased flow velocity or an increased cluster temperature.…”

Section: Applicationsmentioning

confidence: 99%

Ultra-precise particle velocities in pulsed supersonic beams

Christen

2013

The Journal of Chemical Physics

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We describe an improved experimental method for the generation of cold, directed particle bunches, and the highly accurate determination of their velocities in a pulsed supersonic beam, allowing for high-resolution experiments of atoms, molecules, and clusters. It is characterized by a pulsed high pressure jet source with high brilliance and optimum repeatability, a flight distance of few metres that can be varied with a tolerance of setting of 50 μm, and a precision in the mean flight time of particles of better than 10(-4). The technique achieves unmatched accuracies in particle velocities and kinetic energies and also permits the reliable determination of enthalpy changes with very high precision.

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Transferring pharmaceuticals into the gas phase

Cited by 9 publications

References 22 publications

Argon Solvent Effects on Optical Properties of Silver Metal Clusters

Argon Solvent Effects on Optical Properties of Silver Metal Clusters

Probing free jet expansions of supercritical fluids

Ultra-precise particle velocities in pulsed supersonic beams

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