Isotope effect and proton hopping in high-temperature protonic conductors

✍ Scribed by A.S Nowick; A.V Vaysleyb

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 559 KB
• Volume: 97
• Category: Article
• ISSN: 0167-2738
• DOI: 10.1016/s0167-2738(97)00081-7

✦ Synopsis

Studies of the 'isotope effect' in proton migration most often involve substitution of D for H. In the case of high-temperature protonic conductors (HTPCs) having the perovskite structure, Arrhenius behavior of the conductivity is consistently found, with activation energy for deuterium E . E by 0.03 to 0.06 eV, and a ratio of preexponentials D H

A /A ,1. In addition, the magnitude of the preexponentials is generally lower than expected by about one order of H D magnitude. These results are examined in terms of four theories. Satisfactory description of the principal facts is given by a formal semi-classical theory, which is widely used in chemistry, and alternatively by the escape theory, originated by Kramers, which treats collisions of a light atom with a matrix of more massive atoms.