DIAGRAM OF STATE AND THERMODYNAMIC PROPERTIES OF PURE ISOTOPES AND OF ISOTOPIC SOLUTIONS (in French)
The variation of the residual energy at absolute zero with the molecular mass is the principal cause of differences appearing in the diagrams of state of pure isotopes of the same chemicai constituent. Each isotope can be characterized by the quantum parameter A (introduced by Boer) that represents, in fact, a reduced de Broglie wavelength. A quantum generalization of the classical theorem of corresponding states permits the experimental results to be interpreted and coordinated. It is necessary to take into consideration a very slight modification of the intermolecular forces with the passage of one isotopic molecule to another. Completely negligible for light isotopes (He and H/sub 2/), this effect can be dominant for heavy isotopes (h-cyclohexane and d-cyclohexane). With respect to solid and liquid isotopic solutions, studies made by statistical mechanics indicate a positive excess free energy g/sup E/ and, consequently, a demixture at sufficiently low temperature. Experimentally, it was found that g/ sup E/ > 0 for the liquid solutions He/sup 3/- He/sup 4/, H/sub 2/-D/sub 2/, and H/sub 2/-HD and for the solid solution H/sub 2/- D/sub 2/ . The only known example of isotopic demixture at the present is given by the system He/sup 3/- He/ sup 4/. (tr-auth)
- Research Organization:
- Universite Libre, Brussels
- NSA Number:
- NSA-17-023330
- OSTI ID:
- 4716189
- Journal Information:
- Journal de Chimie Physique (France) Merged with Rev. Gen. Colloides to form J. Chim. Phys. Rev. Gen. Colloides, Vol. Vol: 60; Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Country unknown/Code not available
- Language:
- French
Similar Records
Reaction and reorientation of electronically excited H2(B)
Reaction and reorientation of electronically excited H[sub 2](B)