OSA's Digital Library

Applied Optics

Applied Optics

APPLICATIONS-CENTERED RESEARCH IN OPTICS

  • Vol. 5, Iss. 8 — Aug. 1, 1966
  • pp: 1285–1291

On the Question of Equilibrium in Mercury + Thallium Iodide Arc Discharges

C. F. Gallo  »View Author Affiliations


Applied Optics, Vol. 5, Issue 8, pp. 1285-1291 (1966)
http://dx.doi.org/10.1364/AO.5.001285


View Full Text Article

Enhanced HTML    Acrobat PDF (1244 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

Two aspects of the concept of local thermodynamic equilibrium are examined in medium-pressure, mercury arc discharges with thallium iodide additives. It is shown theoretically that the experimental intensity of the Tl 5350 Å line is reasonably consistent with a Boltzmann distribution of excited states. In fact, it is theoretically and experimentally shown that self-absorption is a major factor in limiting the intensity of the bright thallium 5350 Å line even though Ti is a minor constituent in the discharge and even though this line does not terminate on the ground state. The dramatic spectral inhomogeneity that develops in long, horizontal, ac discharges with excess TlI in the presence of a longitudinal temperature gradient is examined in detail. Both emission and absorption studies show that the spectral inhomogeneity is caused by a large gradient in the thallium concentration. This inhomogeneous distribution of TlI vapors is caused by an inhomogeneous and unsymmetrical distribution of condensed TlI along the tube walls which results from the temperature gradient. In turn, the temperature gradient is increased by the ionization of thallium which locally decreases the electrical resistivity, electric field, and power input to the arc. Thus, an equilibrium distribution of TlI vapors is attained only if the distribution of condensed TlI is reasonably uniform and the tube geometry and pressure are favorable for rapid diffusion of the vapors. The inhomogeneity also disappears if a sufficiently small quantity of solid TlI is added to the lamp so that it is all vaporized.

© 1966 Optical Society of America

History
Original Manuscript: February 14, 1966
Published: August 1, 1966

Citation
C. F. Gallo, "On the Question of Equilibrium in Mercury + Thallium Iodide Arc Discharges," Appl. Opt. 5, 1285-1291 (1966)
http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-5-8-1285

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Log in to access OSA Member Subscription

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited