Refractive index of the alkali halides .1. Constant joint density of states model

被引:20
作者
Johannsen, PG
机构
[1] Fachbereich Physik, Universität GH Paderborn
关键词
D O I
10.1103/PhysRevB.55.6856
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
The electronic contribution to the imaginary part of the dielectric function of the alkali halides is assumed to be proportional to E(-2) above the onset of optical absorption, which is equivalent to the assumption of a constant joint density of states (CJDOS) model. In this approach the electronic contribution to the refractive index can be described by two parameters, the long-wavelength limit of the refractive index n(infinity) and the frequency of the onset of optical absorption E(x0). Various fits of the corresponding model function to experimental dispersion data show that E(x0) is closely related to the frequency of the lowest exciton. Exciton absorption and interband transitions from the p valence bands to s and d conduction bands make the main contributions to the imaginary part of the dielectric function. The relative shifts of the s and d bands with respect to the p bands with density have different signs, and make different contributions to the photoelastic behavior. The CJDOS model is extended to account for the different behavior of s and d bands, and it is shown that the available literature data for the density dependence of the refractive index can be related to the energies of the s and d bands, derived from optical spectra and band-structure calculations. Shock data for LiF and NaCl are discussed, as well as low-pressure results for KCl, KBr, and KI. Recent high-pressure results for CsI show a strong nonlinear density dependence of the refractive index, in contrast to the almost linear behavior of the lighter alkali halides. Within the CJDOS model, this nonlinear behavior can be related to the closure of the band gap in CsI.
引用
收藏
页码:6856 / 6864
页数:9
相关论文
共 50 条
[41]   STUDY OF EFFECTIVE DEBYE TEMPERATURE IN ALKALI-METALS AND THEIR HALIDES .1. INTRODUCTION [J].
TRIPATHI, ND ;
PANDEY, SK .
ACUSTICA, 1976, 35 (04) :278-280
[42]   STRUCTURE OF ADSORBATES ON ALKALI-HALIDES (THEORY) .1. HBR ON LIF(001) [J].
POLANYI, JC ;
WILLIAMS, RJ ;
OSHEA, SF .
JOURNAL OF CHEMICAL PHYSICS, 1991, 94 (02) :978-996
[43]   CONDUCTANCE OF ALKALI HALIDES .1. POTASSIUM CHLORIDE IN DIOXANE-WATER MIXTURES [J].
LIND, JE ;
FUOSS, RM .
JOURNAL OF PHYSICAL CHEMISTRY, 1961, 65 (06) :999-&
[44]   STUDIES ON THE FREEZING OF PURE LIQUIDS .1. CRITICAL SUPERCOOLING IN MOLTEN ALKALI HALIDES [J].
BUCKLE, ER ;
UBBELOHDE, AR .
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL AND PHYSICAL SCIENCES, 1960, 259 (1298) :325-&
[45]   STUDIES ON AG CENTERS IN ALKALI HALIDES .1. NATURE OF OPTICAL TRANSITIONS - KCL [J].
KOJIMA, K ;
SHIMANUKI, S ;
MAKI, M ;
KOJIMA, T .
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 1970, 28 (05) :1227-+
[46]   DEPENDENCE OF MELTING POINTS OF ALKALI-METAL HALIDES ON COMPOSITION AND STRUCTURE .1. DEPENDENCE OF MELTING POINTS OF ALKALI METAL HALIDES ON ATOM PARAMETERS [J].
KAZRAGIS, AP .
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY,USSR, 1970, 44 (07) :927-&
[47]   A MODEL FOR OPTICAL TRANSITIONS BETWEEN BOUND STATES FOR F-CENTERS IN ALKALI HALIDES [J].
IADONISI, G ;
PREZIOSI, B .
NUOVO CIMENTO B, 1967, 48 (01) :92-&
[48]   SOLUBILITY OF GASES IN MELTED HALIDES OF ALKALI-METALS .1. GENERAL THEORY [J].
NOVOZHILOV, AL ;
KHAIMENOV, AP .
ZHURNAL FIZICHESKOI KHIMII, 1976, 50 (10) :2457-2460
[49]   ELECTRONIC BAND-STRUCTURE OF ALKALI-HALIDES .1. EXPERIMENTAL PARAMETERS [J].
POOLE, RT ;
JENKIN, JG ;
LIESEGANG, J ;
LECKEY, RCG .
PHYSICAL REVIEW B, 1975, 11 (12) :5179-5189
[50]   ISOMERISM OF DIMERIC SALT MOLECULES IN THE VAPOR PHASE .1. ALKALI METAL HALIDES [J].
YARYMAGAEV, NL .
ZHURNAL FIZICHESKOI KHIMII, 1964, 38 (11) :2579-2586