farkas_1934#
A. Farkas, L. Farkas and P. Harteck, “Experiments on Heavy Hydrogen. II. The Ortho-Para Conversion”, Proc. R. Soc. London A 144, 481 (1934)
Source record · Catalogue · Review register
Source kind: measurement
Recorded technique: Catalytic ortho-para conversion of ‘diplogen’ (D2, about 90 % D) on active charcoal at 20.4, 53 and 78 K, the ortho/para content measured by the thermal conductivity micro-method of A. Farkas (two cells, resistance changes, Tables I-II); comparison with the concentrations calculated for Fermi-Dirac and Bose-Einstein statistics and nuclear spins 1/2 and 1 (Table III); the reconversion by oxygen at 293 K (pp. 482-491).
Materials in structured entries: None recorded.
Dataset quantities: None recorded.
Contents: 0 datasets; 0 formulas.
Curation notes#
A JSTOR reprint (pdf page 1 is the JSTOR cover; pdf page 2 = p. 481: Proc. R. Soc. Lond. A 144, No. 852, 29 March 1934, received 2 March 1934); identity VALIDATED_WITH_WARNINGS; first page checked. Page numbers are journal pages (pdf page + 479).
What the paper states about the D2 spin statistics (TC-105): the high- temperature ortho:para ratio is g_ortho/g_para = (t + 1)(2t + 1)/(t(2t + 1)) = (t + 1)/t, ‘g is the nuclear statistical weight, being (t + 1)(2t + 1) for the ortho states, and t(2t + 1) for the para states’ (p. 482), t the nuclear spin; with Bose-Einstein statistics ‘all rotational states with even quantum numbers, are ortho states, and have the higher statistical weight’ (p. 486), ‘in agreement with the statement of Lewis and Ashley’ (lewis_1933); ‘Our ratios agree better with the spin t = 1’ (p. 487), and normal diplogen is ‘n-D2 = 2/3 o-D2 + 1/3 p-D2’ (p. 488). For t = 1 the printed weights are (t + 1)(2t + 1) = 6 (even J) and t(2t + 1) = 3 (odd J): this paper PRINTS the 6 : 3 that raj_2018 uses, which murphy_1934 gives only as a ratio. Caveat (footnote, p. 487): ‘the measurements cannot exclude definitely a nuclear spin of 1/2 as the relative changes in the concentrations ... are very similar to those for t = 1’; the spectroscopic ratio of murphy_1934 (1.97 +- 0.03 against 3 for spin 1/2) settles it. Summary (pp. 492-493): Bose-Einstein statistics, ‘the most probable value of the nuclear spin of diplogen is 1’; the deuteron magnetic moment ‘about 1/5’ of the proton’s (from the oxygen reconversion).
The measured quantities (Table II: resistance changes relative to normal D2 and their ratios 9.2 (cell I) and 8.8 (cell II) at 20.4 K, 3.4 at 53 K, 1 at 78 K; Table III: the calculated ratios, Bose-Einstein t = 1: 9.5, 3.2, 1) are conversion data, not refractive: not extracted.
No refractive data: no datasets.
Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
No datasets are recorded.
Formulas#
No formulas are recorded.
Corrections#
No dataset errata are recorded in this source record.
Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the review register for the checks and decisions.