Versatile High Pressure Mössbauer Apparatus

Abstract

An apparatus has been developed which permits high pressure Mössbauer resonance studies to 300 kbar. It can be operated with either the source or the absorber under pressure. The pressures are established by x-ray diffraction measurements, and calibration curves are presented for both the supported taper and Bridgman anvils cells. A motion device involving magnets and phosphor bronze springs, with an adjustable mount, is described. Circuits necessary to control the motion, and to distribute the signals from two devices operating in parallel, are outlined.

The Effect of Pressure on the Mössbauer Resonance in Hemin and Iron Phthalocyanine

“…The Mossbauer line arising from the nuclear transition involving the excited level with mI = + 3/2 will be broadened more than the line arising from the m, = ± 1/2 level, and the quadrupole pair will be asymmetric. The probability of a transition between two S, sublevels cLn be determined from the expression W(SZ -* Ss') = C (Sz' S4js)J4xft(S,') (1 -3 cos2 Oj)2/rj6, (1) where1n(S8') = e-ES /IkT eCES./kT is the Boltzmannfactor. Evaluationof equation…”

High Pressure

“…Drickamer and his colleagues (29) have extended the pressure range for X-ray diffraction to about 500 kb by adapting their opposed-anvil apparatus with support on the tapered faces, and Owen & Martin (30) have claimed similar pressures are obtainable with opposed dia mond anvils. Drickamer's apparatus has also been adapted for the Moss bauer effect (31) and for nuclear magnetic resonance (32). Several groups have reported neutron diffraction under pressure [Smith, Bradley & …”

X-Ray Absorption at High Pressure

“…7 The sample, a thin uniform film, approximately 0.3 mmx0.7 mm, was mounted in a gasket of boron and lithium hydride. The sample area was thus parallel to the anvil axis but perpendicular to the collimated x-ray beam.…”