Hostname: page-component-76fb5796d-vvkck Total loading time: 0 Render date: 2024-04-26T07:52:41.176Z Has data issue: false hasContentIssue false

Diffusivity and Nuclear Spin Relaxation Measurements at High Pressure in Methanol

Published online by Cambridge University Press:  10 February 2011

R. F. Marzke
Affiliation:
Department of Physics and Arizona State University, Tempe, AZ 85287
D. P. Raffaelle
Affiliation:
Department of Physics and Arizona State University, Tempe, AZ 85287
G. H. Wolf
Affiliation:
Department of Chemistry, Arizona State University, Tempe, AZ 85287
J. L. Yarger
Affiliation:
Department of Chemistry, University of California at Berkeley, Berkeley, CA 94720
Get access

Abstract

Diffusivity D and nuclear spin relaxation times T1 and T2 have been measured by NMR to 4.0 GPa in methanol, using a diamond anvil cell probe. In pure MeOH, D−1 and T2 show essentially identical activation volumes. However, these are ∼18% larger than the activation volume of viscosity. By relating these observations to an average molecular correlation time a pressure-dependent infinite-frequency shear modulus G∞ can be inferred, using two independent approaches. The relation between diffusivity and viscosity shows increasing departure from Stokes-Einstein behavior with increasing pressure, if a constant hydrodynamic radius is assumed. This departure is attributed to the pressure dependence of G∞, and can be described empirically by a simple modification of the Stokes-Einstein relation.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1] Lee, S-H, Luszczynski, K., Norberg, R.E. and Conradi, M., Rev. Sci. Instrum. 58, 415 (1987).Google Scholar
[2] Halvorson, K.E., Raffaelle, D.P., Wolf, G.H. and Marzke, R.F. in Frontiers of High Pressure Research, Nato ASI Series B 286, 217 (1991).Google Scholar
[3] Angell, C.A. in Relaxation in Complex Systems, edited by Ngai, K. and Wright, G.B., National Technical Information Service, US Department of Commerce, Springfield, VA 22161, p. 1;Google Scholar
Angeli, C.A., J. Non-Cryst. Solids 131–133, 13 (1991).Google Scholar
[4] Marzke, R.F., Raffaelle, D.P., Halvorson, K.E. and Wolf, G.H., J. Non-Cryst. Solids 171–174, 401 (1994).Google Scholar
[5] Yarger, J. L., Nieman, R.A., Wolf, G.H. and Marzke, R.F., J. Magn. Reson. Series A 114, 255 (1995).Google Scholar
[6] Raffaelle, D.P., Marzke, R.F., Yarger, J.L. and Wolf, G.H., Bull. Am. Phys. Soc. 41, 564 (1996).Google Scholar
[7] Slichter, C.P., The Principles of Magnetic Resonance, 3rd ed., Springer-Verlag, New York, 1989, ch.8.Google Scholar
[8] Abragam, A., The Principles of Nuclear Magnetism, Oxford University Press, London, 1961, ch. 8.Google Scholar
[9] Boden, N., in The Plastically Crystalline State, edited by Sherwood, J. N., Wiley-Interscience, New York, 1979, ch. 5.Google Scholar
[10] Slie, W.M. and Madigosky, W.M., J. Chem. Phys. 48, 2810 (1968).Google Scholar
[11] in preparation for submission to J. Chem. Phys.Google Scholar
[12] Cook, R.L., Herbst, C.A. and King, H.E., J. Phys Chem. 97, 2355 (1993).Google Scholar
[13] Brugmans, M.J.P.and Vos, W.L., J. Phys. Chem. 103, 2661 (1995).Google Scholar
[14] Jonas, J. and Akai, A., J. Chem. Phys. 66, 4946 (1979).Google Scholar