Magnetism and the αβ phase transition in solid oxygen

✍ Scribed by Antônio J.R. da Silva; L.M. Falicov

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 380 KB
• Volume: 222
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(94)87071-3

✦ Synopsis

The electronic spectra of a and B solid Or were calculated in a full many-body approach for a cluster consisting of four O2 molecules with periodic boundary conditions. Only the partially occupied n orbitals (sixteen spin-orbitals, eight electrons) were included. The lowest 8 1 many-body states, which correspond to neutral, unexcited molecules, describe accurately the magnetic excitations of the solids. The two phases have very different spectra resulting, even at very low temperatures, in a large difference in the (magnetic) entropy. The calculated entropy difference at 23.9 K (the a-8 phase transition temperature) agrees surprisingly well with the experimentally measured heat of transformation.