TITLE

Full characterization of an intense pulsed hyperthermal molecular beam

AUTHOR(S)
Watanabe, D.; Che, D.-C.; Fukuyama, T.; Hashinokuchi, M.; Teraoka, Y.; Kasai, T.
PUB. DATE
May 2005
SOURCE
Review of Scientific Instruments;May2005, Vol. 76 Issue 5, p055108
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
A molecular beam technique for generating an intense pulsed hyperthermal molecular beam (pulsed HTMB) was developed. The beam source consists of a pulse valve, a cooling-water bottle that protects the pulse valve from heat transfer of the high temperature nozzle, and a nozzle with a heater. The point was a pulse-valve operation with the high temperature nozzle which was 30-mm long and was made of pyrolytic boron nitride. The pulsed HTMB of HCl was practically generated. The total beam intensity of the pulsed HTMB was measured by a quadrupole mass spectrometer. It was determined that the beam intensity of the pulsed HTMB was two orders of magnitude larger than that obtained in continuous-HTMB conditions. The pulsed HTMB of HCl was fully characterized by means of (2+1) resonance-enhanced multiphoton ionization and ion time-of-flight techniques. We found that the velocity distribution of the pulsed HTMB was well expressed as supersonic molecular beams. At the highest nozzle temperature of 1400 K, the mean translational energy value of HCl molecules was 1.38 eV. The translational energy distribution of the pulsed HTMB covered a range from 0.8 to 1.6 eV. The fraction of higher translational energy molecules greater than 1.0 eV was 80% in the 1400 K nozzle. The rotational state distributions of HCl molecules in the pulsed HTMB were expressed as the Boltzmann distribution. While the rotational temperature decreased by an adiabatic expansion of the beam, the vibrational temperature, which was determined by the ratio of the ground-state population to the excited state one, almost equaled the nozzle temperature.
ACCESSION #
17023871

 

Related Articles

  • Design and characterization of late-mixing flash pyrolytic reactor molecular-beam source. Kim, Hahkjoon; Dooley, Kristin S.; Johnson, Elizabeth R.; North, Simon W. // Review of Scientific Instruments;Dec2005, Vol. 76 Issue 12, p124101 

    We report on the design and characterization of an intense pulsed beam source for the generation of expansion-cooled radical species. The source combines both dual pulsed valve late mixing for coexpansion of reactive gases with a pyrolytic end nozzle as a flash kinetic reactor. As a...

  • Multisample matrix-assisted laser desorption source for molecular beams of neutral peptides. Lupulescu, C.; Abd El Rahim, M.; Antoine, R.; Barbaire, M.; Broyer, M.; Dagany, X.; Maurelli, J.; Rayane, D.; Dugourd, Ph. // Review of Scientific Instruments;Dec2006, Vol. 77 Issue 12, p125102 

    We developed and tested a multisample laser desorption source for producing stable molecular beams of neutral peptides. Our apparatus is based on matrix-assisted laser desorption technique. The source consists of 96 different targets which may be scanned by a software control procedure. Examples...

  • Production of a slit skimmer for use in cold supersonic molecular beams. Subramanian, Ranga; Sulkes, Mark // Review of Scientific Instruments;Jan2008, Vol. 79 Issue 1, p016101 

    Cold molecular beams generated by skimming pulsed supersonic gas expansions normally employ conical skimmers. The use of slit shaped skimmers instead of conical skimmers can afford significant signal enhancements. At this time, however, slit shaped skimmers are not available commercially. We...

  • Response compensation of thermistors: Frequency response and identification of thermal time constant. Tagawa, M.; Kato, K.; Ohta, Y. // Review of Scientific Instruments;Mar2003, Vol. 74 Issue 3, p1350 

    The purpose of this study is to improve the accuracy of general-purpose temperature sensors (commercially available thermistors) in fluctuating temperature measurement and to extend their applicability. First, heat transfer models reflecting the internal structures of plate-type and spherical...

  • An instrument for the heat flux measurement from a contour of a surface with uniform temperature. Baughn, J. W.; Hoffman, M. A.; Lee, Daehee // Review of Scientific Instruments;Mar94, Vol. 65 Issue 3, p689 

    An instrument for the measurement of the heat flux distribution along an internal or external contour of a surface with a uniform temperature is described. The main element in this instrument is an electrically heated narrow nickel/chromium ribbon which is mounted flush with, but thermally and...

  • Improved hot-wire procedure for thermophysical measurements under pressure. Håkansson, B.; Andersson, P.; Bäckström, G. // Review of Scientific Instruments;Oct88, Vol. 59 Issue 10, p2269 

    A new and simplified version of the circuitry for the transient hot-wire method is presented. The circuitry provides a wide range of currents allowing probe wires of various diameters to be used in order to match the thermal properties of the specimen to be investigated. The analysis of the...

  • Temperature dependence of the band gap of ZnSe1-xOx. Broesler, R.; Haller, E. E.; Walukiewicz, W.; Muranaka, T.; Matsumoto, T.; Nabetani, Y. // Applied Physics Letters;10/12/2009, Vol. 95 Issue 15, p151907 

    We have studied the temperature dependence of the band gap of molecular-beam-epitaxy-grown ZnSe1-xOx films (x=0–0.021) using photoluminescence spectroscopy from 15 to 280 K. The temperature dependence of the band gap decreases with increasing oxygen concentration, which can be...

  • Rotatable source crossed molecular beams apparatus with pulsed ultraviolet/vacuum ultraviolet... Willis, P.A.; Stauffer, H.U.; Hinrichs, R.Z.; Davis, H.F. // Review of Scientific Instruments;Jun99, Vol. 70 Issue 6, p2606 

    Describes a universal crossed molecular beams apparatus for studies of bimolecular chemical reaction dynamics. Device's use of two rotatable molecular beam sources; Design features; Performance evaluation.

  • Valved molecular beam skimmer. Marceca, Ernesto; Becker, Jorg A.; Hensel, Friedrich // Review of Scientific Instruments;Aug1997, Vol. 68 Issue 8, p3258 

    Presents the design of a vacuum-tight valve which allows the aperture of the molecular beam skimmer to be closed by plugging a needle directly against its conical wall. Valve operation; Better measurement of helium conductance.

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics