The surface tension of nitric oxide and the corresponding states principle

• Published in: Molecular physics Vol. 91; no. 4; pp. 757 - 760
• Main Authors: CALADO, By JORGE CARREIRA GONCALVES, MENDONCA, ANGELA FILOMENA SIMOES DOS SANTOS, SARAMAGO, BENILDE DE JESUS VIEIRA, SOARES, VIRGILIO ALBERTO MEIRA
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01.07.1997
• ISSN: 0026-8976; 1362-3028
• DOI: 10.1080/002689797171247

An application of the corresponding states principle to the surface tension of nitric oxide NO is presented. The study of NO is especially appealing because it is formed by one of the simplest molecules capable of forming dimers but not larger aggregates. This compound is known to be virtually unassociated in the gaseous state, but to be wholly dimerized in the solid and partially associated in the liquid states. The question of dimerization of nitric oxide in the gas phase was first examined in the light of the principle of corresponding states, applied to the second virial coefficient, by E. A. Guggenheim (1966, Molec. Phys., 10, 401) and R. L. Scott (1966, Molec. Phys., 11, 399). Our experimental results for the surface tension of liquid nitric oxide, reported elsewhere (Calado, J. C. G., et al., 1997, J. Colloid Interface Sci. (in the press)), have already been analysed using a mean field theory (Calado, J. C. G., et al., 1997, J. Colloid Interface Sci. 185, 68). The present paper provides some additional means of interpreting the unique surface behaviour of NO: the surface tension decreases when the temperature increases, as expected, but it does so at a substantially higher rate than is usually observed.