Thermal expansion of alkali halides from 70 to 570 K

Abstract

The thermal expansion of 15 alkali halides has been investigated from 70 to 570 K. The single-crystal specimens of LiF, LiCl, LiBr, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KI, RbI, CsCl, CsBr, and CsI are examined using a high-precision differential dilatometer in conjunction with an electronic micrometer. The results are compared with those available in the literature and are found to be in reasonable agreement. The Grüneisen parameter γ has been calculated using the present thermal expansion data. For a given cation group, the value of γ is very close, but increase in the cation size decreases γ slightly. The indications are that in the temperature range under investigation γ increases very slowly with temperature.

Thermal Expansion of Caesium Halides with the CsCl Structure

“…Their thermal expansion can help us understand the nature of interatomic forces between ions. Many experiments have measured the thermal expansion of caesium halides (Bridgman, 1932;Menary, Ubbelohde & Woodward, 1951;Johnson, Agron & Bredig, 1955;Krishnan & Srinivasan, 1956;Pathak & Pandya, 1960;Whittemore, 1962;Christian & Lynch, 1964;Majumdar & Roy, 1965;James & Yates, 1965;White, 1965;Morlin & Tremmel, 1966;Bailey & Yates, 1967;Pathak & Vasavada, 1970;Fullam, 1972;White & Collins, 1973;Srivastava & Merchant, 1973;Rapp & Merchant, 1973;Panter, 1974;Ganesan & Girirajan, 1986). Most of the data are listed in the book by Touloukian, Kirby, Taylor & Lee (1977).…”

Extended temperature dependence of elastic constants in cubic crystals

“…Table 1 Temperature coefficients TC IJ (10 6 Pa K À1 ) and T 2 C IJ (10 3 Pa K À2 ) for some cubic crystals at room temperature. The data on the elastic constants and temperature coefficients of linear expansion for NaCl were taken from [22,23], respectively, for KCl from [22,24], for KBr from [22,25], for NaBr from [22,26], for KF from [22,27], for AgCl from [22,28], for Au from [29,30], and for Ag from [29,31] number of cubic crystals. In particular, they are important if the temperature dependence deviates from linear behavior.…”

Anharmonic effect on the equation of state (EoS) for NaCl

“…2). We note that the total number of experimental data for α(0, T) is 67 (Enck and Dommel 1965;Pathak and Vasavada 1970;Kirby et al 1972;Rapp and Merchant 1973;Spinolo et al 1979;Ming et al 1983) in the temperature range 300-800 K, with most of these values inside the tolerance (91 % or 61 out of 67 data). Similarly, the tolerance of C P (0, T) is estimated to be 10 times greater than the error calculated from ε ij (error bars in Fig.…”

“…Before calculating the CTEoS, we fit each experimental α(0, T) and C P (0, T) value to the empirical formula where T is the absolute temperature. For the α(0, T) curve, prior to fitting, the measurement data (Rubin et al 1961;Yates and Panter 1962;Enck and Dommel 1965;Meincke and Graham 1965;White 1965;Pathak and Vasavada 1970;Kirby et al 1972;Rapp and Merchant 1973;Legge et al 1979;Spinolo et al 1979;Ming et al 1983), e.g., dL dT P L 293K , have been corrected with the thermodynamic definition, Powell and Fletcher (1965) as used in Spetzler et al (1972) α ≡ ∂V ∂T P V. Fitting C P (0, T) requires the C P (Leadbetter and Settatree 1969) and enthalpy (Magnus 1913;Roth and Bertram 1929;Dawson et al 1963;Holm and Grønvold 1973;Archer 1997) data to be used simultaneously. Table 1 shows both fitting results.…”