The order-disorder phase transition of the Rh(111)-(√3 x √3)R30°-CO phase was investigated by He scattering. The critical temperature turned out to be 330±5 K, while the critical exponents are consistent with a phase transition belonging to the 3-state Potts universality class. The temperature dependence below the critical temperature of both CO phases was studied using elastic He scattering and LEED. These measurements demonstrate that a simple Debye-Waller evaluation of the diffraction data is not appropriate to provide information on the vibrational properties of the CO molecules. From LEED measurements at low temperatures (<70 K) and various CO partial pressures there is evidence of the formation of a disordered second CO layer in equilibrium with the gas phase. The isosteric heat of CO adsorption in the second layer is about 6 kJ mol-1
Temperature behavior of the (sqrt3 x sqrt3)R30-1CO and the (2 x 2)-3CO overlayers on Rh(111): A combined HAS and LEED investigation / Over, H.; Schwegmann, S.; Ertl, G.; Cvetko, D.; DE RENZI, Valentina; Floreano, L.; Gotter, R.; Morgante, A.; Peloi, M.; Tommasini, F.; Zennaro, S.. - In: SURFACE SCIENCE. - ISSN 0039-6028. - STAMPA. - 376:(1997), pp. 177-184.
Temperature behavior of the (sqrt3 x sqrt3)R30-1CO and the (2 x 2)-3CO overlayers on Rh(111): A combined HAS and LEED investigation
DE RENZI, Valentina;
1997
Abstract
The order-disorder phase transition of the Rh(111)-(√3 x √3)R30°-CO phase was investigated by He scattering. The critical temperature turned out to be 330±5 K, while the critical exponents are consistent with a phase transition belonging to the 3-state Potts universality class. The temperature dependence below the critical temperature of both CO phases was studied using elastic He scattering and LEED. These measurements demonstrate that a simple Debye-Waller evaluation of the diffraction data is not appropriate to provide information on the vibrational properties of the CO molecules. From LEED measurements at low temperatures (<70 K) and various CO partial pressures there is evidence of the formation of a disordered second CO layer in equilibrium with the gas phase. The isosteric heat of CO adsorption in the second layer is about 6 kJ mol-1File | Dimensione | Formato | |
---|---|---|---|
temperature_dependece_O_CO_SS97.pdf
Accesso riservato
Tipologia:
Versione dell'autore revisionata e accettata per la pubblicazione
Dimensione
612.66 kB
Formato
Adobe PDF
|
612.66 kB | Adobe PDF | Visualizza/Apri Richiedi una copia |
Pubblicazioni consigliate
I metadati presenti in IRIS UNIMORE sono rilasciati con licenza Creative Commons CC0 1.0 Universal, mentre i file delle pubblicazioni sono rilasciati con licenza Attribuzione 4.0 Internazionale (CC BY 4.0), salvo diversa indicazione.
In caso di violazione di copyright, contattare Supporto Iris