Scaramuzzi, F. and Savoia, A. and Goodstein, D. L. and Cole, M. W. (1977) Viscosity and positive-ion mobility near the melting transition in liquid (4)He. Physical Review B, 16 (7). pp. 3108-3121. ISSN 1098-0121. http://resolver.caltech.edu/CaltechAUTHORS:SCAprb77
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New measurements are presented of the shear viscosity η and the positive-ion mobility μ near the melting transition in liquid 4He. Interpreted in terms of the Stokes law for the drag on a sphere in a viscous medium, it is found, contrary to expectation, that the effective radius of the ion remains constant or decreases slightly as the melting transition is approached at constant temperature. Attempts to explain this observation have not been successful. On the other hand, an older mystery concerning the effective radius of the ion is cleared up: Ahlers and Gamota, comparing data for η and μ at the vapor pressure curve found that the effective radius has a maximum 40 mK below the λ transition (i.e., the lower triple point). We have observed a similar maximum on the melting curve, 40 mK below the upper triple point. It is shown that these maxima may be accounted for by an electrostrictively induced λ transition around the ion. In this interpretation, the maximum along the melting curve serves as the first empirical evidence that the λ line extends into the region of supercooled liquid at pressures above the melting curve.
|Additional Information:||©1977 The American Physical Society. Received 6 May 1977. We are indebted to L. Bruschi and M. Santini for preparing the vibrating-wire viscometer module for us, to T. J. Sluckin for help in data reduction, to R. W. Zwanzig and J. Mathews for valuable theoretical insights concerning the hydrodynamic problem, and to L. Mori for technical assistance.|
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|Deposited By:||Tony Diaz|
|Deposited On:||25 Mar 2006|
|Last Modified:||26 Dec 2012 08:48|
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