A modified Bragg and Williams approximation of the two-step spin crossover

被引：30

作者：

Koudriavtsev, AB ^{[1
]}

机构：

[1] D Mendeleev Univ, Analyt Ctr D, Moscow 125047, Russia

来源：

CHEMICAL PHYSICS | 1999年 / 241卷 / 01期

关键词：

D O I：

10.1016/S0301-0104(98)00405-4

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The expressions for free energy of a binary mixture with chemical equilibrium in a simple cubic lattice have been obtained as functions of energy spacings and degree of ordering supposing that the partition function of a molecule in a lattice centre is dependent on the nature of two nearest neighbours along each normal coordinate. The derived equations contain linear, square and cubic (besides logarithmic) terms with respect to mole fraction of reactants as well as quadratic terms with respect to the degree of ordering. Under simplifying conditions these equations are transformed into the equations of regular solutions theory. The Bragg-Williams approximation of binary ordered system employing regular solution theory expressions for free energy qualitatively predicts a two-step spin crossover. The use of modified expressions for free energy in a Bragg and Williams approximation results in a quantitative description of literature data on the two-step spin-crossover in [Fe(2-pic)(3)]Cl2EtOH. (C) 1999 Elsevier Science B.V. All rights reserved.

引用

页码：109 / 126

页数：18

共 19 条

[1] 2-STEP SPIN CONVERSION OF [FE-II(5-NO2-SAL-N(1,4,7,10))] - 292, 153, AND 103 K X-RAY CRYSTAL AND MOLECULAR-STRUCTURE AND INFRARED, MAGNETIC, MOSSBAUER, CALORIMETRIC, AND THEORETICAL-STUDIES [J].

BOINNARD, D ;

BOUSSEKSOU, A ;

DWORKIN, A ;

SAVARIAULT, JM ;

VARRET, F ;

TUCHAGUES, JP .

INORGANIC CHEMISTRY, 1994, 33 (02) :271-281

[2]

BOUSSEKSOU A, 1995, J PHYS I, V5, P747, DOI 10.1051/jp1:1995165

[3]

BOUSSEKSOU A, 1992, J PHYS I, V2, P1381, DOI 10.1051/jp1:1992217

[4] 2-LEVEL MODELS FOR THE 2-STEP SPIN CROSSOVERS [J].

BOUSSEKSOU, A ;

NASSER, J ;

LINARES, J ;

BOUKHEDDADEN, K ;

VARRET, F .

MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 1993, 234 :269-274

[5] Ising-like model for the two step spin-crossover of binuclear molecules [J].

Bousseksou, A. ;

Varret, F. ;

Nasser, J. .

Journal De Physique, I, 1993, 3 (06)

[6]

Fowler R. H., 1939, STAT THERMODYNAMICS

[7]

GUETLICH P, 1990, COORDIN CHEM REV, V97, P1

[8]

GUETLICH P, 1994, ANGEW CHEM INT EDIT, V33, P2024

[9]

Hirschfelder J. O., 1967, MOL THEORY GASES LIQ

[10] THERMODYNAMICS OF THE SPIN TRANSITION IN [FEXZN1-X(2-PIC)3]CL2.ETOH [J].

JAKOBI, R ;

SPIERING, H ;

GUTLICH, P .

JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS, 1992, 53 (02) :267-275

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