By using the method of desorption from previously saturated specimens, the coefficients of diffusion were determined in single crystals at 473 to 823K. The data (tables 168 and 169) could be described by:

3He:     D (cm2/s) = 1.8 x 10-2 exp[-0.36(eV)/kT]

4He:     D (cm2/s) = 1.5 x 10-2 exp[-0.36(eV)/kT]

L.V.Gulin, P.V.Volobuev, I.A.Korolev, P.E.Suetin: Fizika Tverdogo Tela, 1977, 19[4], 1017-20

 

 

Table 168

Diffusivity of He in RbCl Single Crystals

 

Isotope

Temperature (K)

D (cm2/s)

3He

823

1.12 x 10-4

3He

773

7.69 x 10-5

3He

723

5.48 x 10-5

3He

673

3.54 x 10-5

3He

623

2.27 x 10-5

3He

573

1.15 x 10-5

3He

523

0.65 x 10-5

3He

473

0.20 x 10-5

4He

823

9.48 x 10-5

4He

773

6.52 x 10-5

4He

723

4.80 x 10-5

4He

673

2.91 x 10-5

4He

623

1.99 x 10-5

4He

573

0.96 x 10-5

4He

523

0.62 x 10-5

4He

473

0.17 x 10-5

 

 

 

Table 169

Isotope Effect for 3He and 4He Diffusion

in RbCl Single Crystals

 

Temperature (K)

D3/D4

823

1.18

773

1.18

723

1.14

673

1.22

623

1.14

573

1.20

523

1.05

473

1.18