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Title: Diffuse scattering from the liquid-vapor interfaces of dilute Bi:Ga, Tl:Ga, and Pb:Ga alloys

Abstract

As part of a study of the in-plane wave-vector (q{sub xy}) dependence of the effective Hamiltonian for the liquid-vapor interface, H(q), the wave-vector dependences of diffuse x-ray scattering from the liquid-vapor interfaces of dilute alloys of Bi in Ga, Tl in Ga, and Pb in Ga have been measured. In these dilute alloys the solute component segregates as a monolayer that forms the outermost stratum of the liquid-vapor interfaces, and the density distribution along the normal to the interface is stratified. Over the temperature ranges that the alloy interfaces were studied, the Tl and Pb monolayers exhibit both crystalline and liquid phases while the Bi monolayer is always liquid. The diffuse scattering from the liquid-vapor interfaces of these alloys displays interesting differences with that from the liquid-vapor interface of pure Ga. The presence of a segregated monolayer of solute in the liquid-vapor interface of the alloy appears to slightly suppress the fluctuations in an intermediate wave-vector range in a fashion that preserves the validity of the macroscopic capillary wave model to smaller wavelengths than in pure liquid Ga, and there is an increase in diffuse scattering when the Tl and Pb monolayers melt. The surface intrinsic roughness from fitting themore » wave-vector dependence of surface tension is 5.0 pm for the Tl:Ga alloy and 1.4 pm for the Bi:Ga alloy. Also, a mode of excitation that contributes to diffuse scattering from the liquid-vapor interface of Pb in Ga, but does not contribute to diffuse scattering from the liquid-vapor interface of Ga, has been identified. It is proposed that this mode corresponds to the separation of the Pb and Ga layers in the regime 1 nm{sup -1}{<=}q{sub xy}{<=}10 nm{sup -1}.« less

Authors:
; ;  [1];  [1];  [2];  [3]
  1. Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637 (United States)
  2. (United States)
  3. CARS, University of Chicago, Chicago, Illinois 60637 (United States)
Publication Date:
OSTI Identifier:
20787774
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 72; Journal Issue: 23; Other Information: DOI: 10.1103/PhysRevB.72.235426; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BISMUTH ALLOYS; CAPILLARIES; DENSITY; DIFFUSE SCATTERING; DILUTE ALLOYS; DISTRIBUTION; EXCITATION; EXCITED STATES; FLUCTUATIONS; GALLIUM ALLOYS; HAMILTONIANS; INTERFACES; LAYERS; LEAD ALLOYS; LIQUIDS; ROUGHNESS; SURFACE TENSION; SURFACES; TEMPERATURE DEPENDENCE; THALLIUM ALLOYS; VAPORS; VECTORS; X-RAY DIFFRACTION

Citation Formats

Li Dongxu, Jiang Xu, Rice, Stuart A., Lin Binhua, CARS, University of Chicago, Chicago, Illinois 60637, and Meron, Mati. Diffuse scattering from the liquid-vapor interfaces of dilute Bi:Ga, Tl:Ga, and Pb:Ga alloys. United States: N. p., 2005. Web. doi:10.1103/PHYSREVB.72.2.
Li Dongxu, Jiang Xu, Rice, Stuart A., Lin Binhua, CARS, University of Chicago, Chicago, Illinois 60637, & Meron, Mati. Diffuse scattering from the liquid-vapor interfaces of dilute Bi:Ga, Tl:Ga, and Pb:Ga alloys. United States. doi:10.1103/PHYSREVB.72.2.
Li Dongxu, Jiang Xu, Rice, Stuart A., Lin Binhua, CARS, University of Chicago, Chicago, Illinois 60637, and Meron, Mati. Thu . "Diffuse scattering from the liquid-vapor interfaces of dilute Bi:Ga, Tl:Ga, and Pb:Ga alloys". United States. doi:10.1103/PHYSREVB.72.2.
@article{osti_20787774,
title = {Diffuse scattering from the liquid-vapor interfaces of dilute Bi:Ga, Tl:Ga, and Pb:Ga alloys},
author = {Li Dongxu and Jiang Xu and Rice, Stuart A. and Lin Binhua and CARS, University of Chicago, Chicago, Illinois 60637 and Meron, Mati},
abstractNote = {As part of a study of the in-plane wave-vector (q{sub xy}) dependence of the effective Hamiltonian for the liquid-vapor interface, H(q), the wave-vector dependences of diffuse x-ray scattering from the liquid-vapor interfaces of dilute alloys of Bi in Ga, Tl in Ga, and Pb in Ga have been measured. In these dilute alloys the solute component segregates as a monolayer that forms the outermost stratum of the liquid-vapor interfaces, and the density distribution along the normal to the interface is stratified. Over the temperature ranges that the alloy interfaces were studied, the Tl and Pb monolayers exhibit both crystalline and liquid phases while the Bi monolayer is always liquid. The diffuse scattering from the liquid-vapor interfaces of these alloys displays interesting differences with that from the liquid-vapor interface of pure Ga. The presence of a segregated monolayer of solute in the liquid-vapor interface of the alloy appears to slightly suppress the fluctuations in an intermediate wave-vector range in a fashion that preserves the validity of the macroscopic capillary wave model to smaller wavelengths than in pure liquid Ga, and there is an increase in diffuse scattering when the Tl and Pb monolayers melt. The surface intrinsic roughness from fitting the wave-vector dependence of surface tension is 5.0 pm for the Tl:Ga alloy and 1.4 pm for the Bi:Ga alloy. Also, a mode of excitation that contributes to diffuse scattering from the liquid-vapor interface of Pb in Ga, but does not contribute to diffuse scattering from the liquid-vapor interface of Ga, has been identified. It is proposed that this mode corresponds to the separation of the Pb and Ga layers in the regime 1 nm{sup -1}{<=}q{sub xy}{<=}10 nm{sup -1}.},
doi = {10.1103/PHYSREVB.72.2},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 23,
volume = 72,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2005},
month = {Thu Dec 15 00:00:00 EST 2005}
}
  • As part of a study of the in-plane wave-vector (q{sub xy}) dependence of the effective Hamiltonian for the liquid-vapor interface, H(q), the wave-vector dependences of diffuse x-ray scattering from the liquid-vapor interfaces of dilute alloys of Bi in Ga, Tl in Ga, and Pb in Ga have been measured. In these dilute alloys the solute component segregates as a monolayer that forms the outermost stratum of the liquid-vapor interfaces, and the density distribution along the normal to the interface is stratified. Over the temperature ranges that the alloy interfaces were studied, the Tl and Pb monolayers exhibit both crystalline andmore » liquid phases while the Bi monolayer is always liquid. The diffuse scattering from the liquid-vapor interfaces of these alloys displays interesting differences with that from the liquid-vapor interface of pure Ga. The presence of a segregated monolayer of solute in the liquid-vapor interface of the alloy appears to slightly suppress the fluctuations in an intermediate wave-vector range in a fashion that preserves the validity of the macroscopic capillary wave model to smaller wavelengths than in pure liquid Ga, and there is an increase in diffuse scattering when the Tl and Pb monolayers melt. The surface intrinsic roughness from fitting the wave-vector dependence of surface tension is 5.0 pm for the Tl:Ga alloy and 1.4 pm for the Bi:Ga alloy. Also, a mode of excitation that contributes to diffuse scattering from the liquid-vapor interface of Pb in Ga, but does not contribute to diffuse scattering from the liquid-vapor interface of Ga, has been identified. It is proposed that this mode corresponds to the separation of the Pb and Ga layers in the regime 1 nm{sup -1} {le} q{sub xy} {le} 10 nm{sup -1}.« less
  • No abstract prepared.
  • We report the results of measurements of x-ray reflectivity and grazing incidence x-ray diffraction from the liquid-vapor interfaces of four dilute alloys of Bi in Ga with mole fractions x{sub Bi} = 0.0032, 0.0023, 0.00037, and 0.000037. The monolayer coverage of the alloys with x{sub Bi} = 0.0023, and x{sub Bi} = 0.00037 is about 0.85 and only very slightly temperature dependent. The monolayer coverage in the lowest-concentration alloy, with x{sub Bi} = 0.000037, ranged from 0.82 at 29 C to 0.58 at 110 C. In none of these alloys, down to the lowest temperature used, 29 C, can wemore » find any evidence for crystallization of the Bi monolayer that segregates as the outermost stratum of the liquid-vapor interface. Drawing on theoretical arguments we propose that the transitions inferred from the second-harmonic generation and plasma generation studies of dilute Bi in Ga alloys are from the liquid state to the hexatic state of the Bi monolayer. The data for the alloy with x{sub Bi} = 0.000037 suggest that near 80 C there is a disordered phase-to-disordered phase transition.« less
  • Surface sensitive X-ray reflectivity (XR), fluorescence (XF), and grazing incidence X-ray diffraction (GIXD) experiments were conducted to determine the accumulation of ferric iron Fe (III) or ferrous iron Fe (II) under dihexadecyl phosphate (DHDP) or arachidic acid (AA) Langmuir monolayers at liquid/vapor interfaces. Analysis of the X-ray reflectivity and fluorescence data of monolayers on the aqueous subphases containing FeCl3 indicates remarkably high levels of surface-bound Fe (III) in number of Fe3þ ions per molecule (DHDP or AA) that exceed the amount necessary to neutralize a hypothetically completely deprotonated monolayer (DHDP or AA). These results suggest that nano-scale iron (hydr) oxidemore » complexes (oxides, hydroxides or oxyhydroxides) bind to the headgroups and effectively overcompensate the maximum possible charges at the interface. The lack of evidence of in-plane ordering in GIXD measurements and strong effects on the surface-pressure versus molecular area isotherms indicate that an amorphous network of iron (hydr) oxide complexes contiguous to the headgroups is formed. Similar experiments with FeCl2 generally resulted with the oxidation of Fe (II)–Fe (III) which consequently leads to ferric Fe (III) complexes binding albeit with less iron at the interface. Controlling the oxidation of Fe (II) changes the nature and amount of binding significantly. The implications to biomineralization of iron (hydr) oxides are briefly discussed.« less
  • The liquid-vapor fractionation fuctors for dilute solutions of HT in e-H/ sub 2/and DT in e-D/sub 2/ were measured over the temperature ranges 13.95 to 30.26 and 18.67 to 32.48 deg K, respectively. At these temperatures the respective fractionation factors are 3.88, 1.24, 1.38, and 1.07. In all cases the heavy isotope concentrates in the liquid phase. The so, lutions obey Henry's law in the concentration range studied (1 to 2 x 10/sup -8/M). The fractionation factors vanish at the critical temperatures of the respective solvents. The differences in the partial molal heats of vaporization of the isotopes are functionsmore » of the temperature. It is shown conclusively that the fractionation factors for the HT-- H/sub 2/ mix tures are appreciably smaller ( approximates 24%) than those to be expected for dilute mixtures of D/sub 2/ in H/sub 2/ ifference in behavior of HT from D/sub 2/ is a manifestation of the effect of the molecular structure on the phase equilibrium properties of the liquid. The principal structural effect ia shown, by comparison of the experimental data with theoretical calculations, to be a coupling of the molecular rotation with the hindered translation of the molecule in the liquid. (auth)« less