First order phase transition in ND4Cl
1972; Elsevier BV; Volume: 11; Issue: 8 Linguagem: Inglês
10.1016/0038-1098(72)90310-9
ISSN1879-2766
Autores Tópico(s)Molecular Spectroscopy and Structure
ResumoWe have measured the order-parameter in the meighborhood of the order-disorder transition in deuterated ammonium chloride as a function of temperature, at atmospheric pressure, by performing structure analysis at each temperature using 1.25Åwavelength neutrons. The order-parameter is discontinuous at the transition temperature (∼ 249°K). Measurement of the intensity of the (221) reflection for increasing and decreasing temperature scans reveals hysteresis (‡ Tc≈0.035°K) establishing that the transition is first-order, as in NH4Cl. Йэmepeн пopядкoбый пapameтp б oкpecтнocтй пepexoдa пopядoк-бecпopядoк б дeйтepйэoбaннom xиopйcтom ammoнйй б эaбйcйmocтй oт тemпepaтypы пpй atmocфepнom дaбиeнйй. Пpoйэбoдйиcя aнaийэ cтpyктypы дия кaждo<jcy; тemпepaтypы c пomoщью нe<jcy;тpoнoб дийннo<jcy; бoины I, 25Å. Ycтaнoбиeннo oтcycтбйe нeпpepыбнocтй y пopядкoбoгo пapameтpa пpй тemпepaтype пepexoдa /∼249°K/. б peэyибтaтe йэmepeнйя йнтeнcйбнocтй oтpaжeнйя /221/ oбнapyжeн гйcтepeэйc пpй yбeийщeнйй й ymeнбшeнйй тemпepaтyы/‡TPinC≈0,035°K/. Этo пйбoдйт к эaкиющeнйю, щтo пepexoд, кaк й б NH4Cl, пepбpoгo poдa.
Referência(s)