scholarly journals Resonant Ionization Using IR Light:  A New Tool To Study the Spectroscopy and Dynamics of Gas-Phase Molecules and Clusters

2003 ◽  
Vol 107 (11) ◽  
pp. 1671-1688 ◽  
Author(s):  
Gert von Helden ◽  
Deniz van Heijnsbergen ◽  
Gerard Meijer
Keyword(s):  
Gas Phase ◽  
Resonant Ionization ◽  
Gas Phase Molecules ◽  
Ir Light

scholarly journals Rapid compressions in a captive bubble apparatus are isothermal

2003 ◽  
Vol 95 (5) ◽  
pp. 1896-1900
Author(s):  
Wenfei Yan ◽  
Stephen B. Hall
Keyword(s):  
Hydrostatic Pressure ◽  
Gas Phase ◽  
Pulmonary Surfactant ◽  
First Order ◽  
First Order Kinetics ◽  
Gas Phase Molecules ◽  
Actual Change ◽  
Phase Temperature ◽  
Two Phases ◽  
Interfacial Films

Captive bubbles are commonly used to determine how interfacial films of pulmonary surfactant respond to changes in surface area, achieved by varying hydrostatic pressure. Although assumed to be isothermal, the gas phase temperature (Tg) would increase by >100°C during compression from 1 to 3 atm if the process were adiabatic. To determine the actual change in temperature, we monitored pressure (P) and volume (V) during compressions lasting <1 s for bubbles with and without interfacial films and used P · V to evaluate Tg. P · V fell during and after the rapid compressions, consistent with reductions in n, the moles of gas phase molecules, because of increasing solubility in the subphase at higher P. As expected for a process with first-order kinetics, during 1 h after the rapid compression P · V decreased along a simple exponential curve. The temporal variation of n moles of gas was determined from P · V >10 min after the compression when the two phases should be isothermal. Back extrapolation of n then allowed calculation of Tg from P · V immediately after the compression. Our results indicate that for bubbles with or without interfacial films compressed to >3 atm within 1 s, the change in Tg is <2°C.

Computational UV Spectra for Amorphous Solids of Small Molecules

2021 ◽  
Author(s):  
Austin Michael Wallace ◽  
Ryan C. Fortenberry
Keyword(s):  
Carbon Dioxide ◽  
Interstellar Medium ◽  
Small Molecules ◽  
Gas Phase ◽  
Amorphous Solids ◽  
Uv Spectra ◽  
Ammonia Water ◽  
Gas Phase Molecules ◽  
High Level

Ices in the interstellar medium largely exist as amorphous solids composed of small molecules including ammonia, water, and carbon dioxide. Describing gas-phase molecules can be readily accomplished with current high-level...

scholarly journals Strongly aligned gas-phase molecules at free-electron lasers

2015 ◽  
Vol 48 (20) ◽  
pp. 204002 ◽  
Author(s):  
Thomas Kierspel ◽  
Joss Wiese ◽  
Terry Mullins ◽  
Joseph Robinson ◽  
Andy Aquila ◽  
...  
Keyword(s):  
Gas Phase ◽  
Free Electron ◽  
Free Electron Lasers ◽  
Gas Phase Molecules

scholarly journals Evolutionary Models of Interstellar Chemistry

1992 ◽  
Vol 150 ◽  
pp. 205-210
Author(s):  
Sheo S. Prasad
Keyword(s):  
Gas Phase ◽  
Chemical Processes ◽  
Evolutionary Models ◽  
Evolutionary Perspective ◽  
Interstellar Chemistry ◽  
Interstellar Clouds ◽  
Dynamical Equilibrium ◽  
Chemical Models ◽  
Gas Phase Molecules ◽  
Fixed Condition

Evolutionary chemical models are ultimately unavoidable for a full understanding of interstellar clouds. They include not only the chemical processes but also the dynamical processes by which the modeled object came to be the way it is. From an evolutionary perspective, dark cores may be ephemeral objects and dynamical equilibrium an exception rather than norm. Evolutionary models have numerous advantages over “classical” fixed condition equilibrium models. They have the potential to provide more elegant explanations for the observed inter-cloud and intra-cloud chemical differences. The problem of the depletion of gas phase molecules by condensation onto the grain may also be less serious in evolutionary models. Hence, these models should be actively developed.

scholarly journals Chemical Models of Collapsing Envelopes

2000 ◽  
Vol 197 ◽  
pp. 51-60
Author(s):  
Edwin A. Bergin
Keyword(s):  
Star Formation ◽  
Gas Phase ◽  
Chemical Evolution ◽  
Molecular Ions ◽  
Polar Molecules ◽  
Mass Star ◽  
Chemical Models ◽  
Gas Phase Molecules ◽  
Low Mass

We discuss recent models of chemical evolution in the developing and collapsing protostellar envelopes associated with low-mass star formation. In particular, the effects of depletion of gas-phase molecules onto grain surfaces is considered. We show that during the middle to late evolutionary stages, prior to the formation of a protostar, various species selectively deplete from the gas phase. The principal pattern of selective depletions is the depletion of sulfur-bearing molecules relative to nitrogen-bearing species: NH3 and N2H+. This pattern is shown to be insensitive to the details of the dynamics and marginally sensitive to whether the grain mantle is dominated by polar or non-polar molecules. Based on these results we suggest that molecular ions are good tracers of collapsing envelopes. The effects of coupling chemistry and dynamics on the resulting physical evolution are also examined. Particular attention is paid to comparisons between models and observations.

scholarly journals X-Ray Diffraction from Isolated and Strongly Aligned Gas-Phase Molecules with a Free-Electron Laser

2014 ◽  
Vol 112 (8) ◽  
Author(s):  
Jochen Küpper ◽  
Stephan Stern ◽  
Lotte Holmegaard ◽  
Frank Filsinger ◽  
Arnaud Rouzée ◽  
...  
Keyword(s):  
Gas Phase ◽  
Free Electron ◽  
Free Electron Laser ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gas Phase Molecules

scholarly journals High-repetition-rate and high-photon-flux 70 eV high-harmonic source for coincidence ion imaging of gas-phase molecules

2016 ◽  
Vol 24 (16) ◽  
pp. 18133 ◽  
Author(s):  
Jan Rothhardt ◽  
Steffen Hädrich ◽  
Yariv Shamir ◽  
Maxim Tschnernajew ◽  
Robert Klas ◽  
...  
Keyword(s):  
Gas Phase ◽  
Repetition Rate ◽  
High Harmonic ◽  
High Repetition Rate ◽  
Photon Flux ◽  
Ion Imaging ◽  
High Repetition ◽  
High Photon Flux ◽  
Gas Phase Molecules ◽  
Harmonic Source
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