Low temperature bulk modulus of solid argon

The lattice parameter of a free-standing argon crystal has been measured as a function of pressure at constant temperature using a high precision back-reflection X-ray camera. Low temperature measurements, using helium as the pressure transmitting fluid, are reported which cover the pressure range of 10 to 300 bar. These measurements, which are the first direct measurements on a free-standing argon crystal in this pressure range, give a P=O, T=O bulk modulus of 28.8±0.4 kbar. This value is in good agreement with the value obtained by extrapolating recent piston-displacement measurements to P=O and also with recent theoretical calculations which incorporate three-body forces. A comparison with values of the P=O, T=O bulk modulus obtained from sound velocity measurements shows significant discrepancies. Experimental difficulties in the sound velocity measurements which could account for these discrepancies are discussed. A survey of experimental and theoretical values of the bulk modulus and elastic constants of solid argon at higher temperatures is presented. The need for further experimental work, particularly elastic constant measurements at intermediate and low temperatures is apparent. Modifications of the apparatus used in the present measurements which would increase the usefulness of the present experimental technique are discussed.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2012

Author dc:creator

• Wilkins, Ronald Wayne

Contributors dc:contributor

• Simmons, R.O.

• argon solids
• bulk modulus

Statement dc:rights

• © Ronald Wayne Wilkins

Language dc:language

en

Identifier

2006378

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/30682