Equilibrium vacancy concentration measurements and thermal properties of solid krypton
Losee, David Lawrence
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/25690
Description
Title
Equilibrium vacancy concentration measurements and thermal properties of solid krypton
Author(s)
Losee, David Lawrence
Issue Date
1967
Doctoral Committee Chair(s)
Simmons, R.O.
Department of Study
Physics
Discipline
Physics
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
equilibrium vacancy
thermal properties
solid krypton
krypton
x-ray lattice parameter expansion
rigid-tail cryostat
Language
en
Abstract
Simultaneous length and x-ray lattice parameter expansion
measurements have been made on three 6 mm diam cylindrical specimens
of 99.995% purity krypton. The specimens were prepared and held
unconstrained in a rigid-tail cryostat in which specimen temperatures
could be precisely controlled. The data show a divergence between
the bulk and lattice expansions at the higher temperatures which
indicates an appreciable concentration of thermally generated defects
o at temperatures above 75 K. The equilibrium atomic vacancy concentration
inferred from these measurements appears to be represented
by n = exp[(2.0 ± 0.5) - (895 ± 1000K)/T]. The monovacancy formation
enthalpy and entropy is discussed and compared with other existing
theoretical and experimental information on argon and krypton. It
appears that the enthalpy of formation for the monovacancy in krypton
may not be entirely accounted for by two-body central-force interactions.
However, existing calculations of the contribution of threebody
interactions to the binding energy of the noble gas solids
appear to be of the correct order of magnitude and sign to produce
agreement between theory and experiment for the vacancy.
Recent measurements of specific heat, isothermal compressibility,
and the present thermal expansivity data, allow compilation
and analysis of a number of thermodynamic functions of solid krypton.
The measurable formation of atomic vacancies at temperatures above
7S oK is seen to make significant contribution to all of the thermal
properties of krypton at the higher temperatures. In the lower
temperature region, the temperature dependence of the equivalent
Debye temperatures for the entropy and for the specific heat,
referred to the volume at TOoK, are examined. Moments of the quasiharmonic
phonon frequency spectrum are deduced as well as the leading
anharmonic coefficient in the free energy. The need for additional
precise experimental information at temperatures near the triple
point of krypton is stressed.
An empirical law of corresponding states is found to
describe several properties of the heavy noble gas solids. Estimates
of the previously unknown activation energy for self-diffusion in
krypton and energies of formation for atomic vacancies in argon and
xenon are possible.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
