The serial sectioning technique was used to study the isotope effect for the diffusion of 22Na and 24Na in single crystals. The results (table 32), for temperatures ranging from 471 to730C, could be described by:

D (cm2/s) = 0.06 exp[-1.29(eV)/kT]

The average 22Na/24Na isotope effect was equal to 0.65.

A.N.Murin, I.V.Murin, V.I.Portnyagin, A.M.Andreev: Fizika Tverdogo Tela, 1973, 15[9], 2838-40

 

 

Table 32

Diffusivity of 22Na in NaBr Single Crystals

 

Temperature (C)

D (cm2/s)

730

2.1 x 10-8

706

1.3 x 10-8

665

7.8 x 10-8

609

2.5 x 10-9

569

1.2 x 10-9

528

8.6 x 10-10

471

2.9 x 10-10