Model-independent determination of the surface scattering-length-density profile from specular reflectivity data
Model-independent determination of the surface scattering-length-density profile from specular reflectivity data
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根据镜面反射率数据独立于模型确定表面散射长度密度分布
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发表时间：
1992
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通讯作者：
J. S. Pedersen
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作者：
J. S. Pedersen
描述了一种分析近地表散射长度密度变化的层状介质的中子和X射线镜面反射率数据的方法。该方法起源于小角散射，它由两个步骤组成：(I)间接傅里叶变换[格拉特(1977)]。J.Appl.克赖斯特。10,415-421]给出了散射长度密度的导数dp/dz的剖面相关函数p(Z)；(Ii)平方根反卷积[格拉特(1981)。J.Appl.克赖斯特。14,101-108]给出了dp/dz和p，即散射长度密度分布。应用该方法的唯一要求是散射长度密度只在有限的范围内变化。在几乎所有情况下，这种方法都不需要对表层的化学成分有任何了解，因此具有一定的客观性。该方法得到了与实验反射率数据相吻合的最光滑轮廓。该方法在一系列不同表面轮廓的模拟反射率数据上进行了测试，并随后用于分析氟碳两亲分子在水和盐溶液中的实验数据。对模拟数据的检验表明，间接傅里叶变换得到的相关函数与原始剖面的相关函数吻合得很好。进一步证明了平方根反褶积方法给出了可靠的散射长度密度分布结果。
An approach for analysing neutron and X-ray specular reflectivity data from stratified media having variation in the scattering-length density near the surface is described. The method has its origin in small-angle scattering and it is composed of two steps: (i) indirect Fourier transformation [Glatter (1977). J. Appl. Cryst. 10, 415-421] giving the profile correlation function p(z) of the derivative dp/dz of the scattering-length density; (ii) square-root deconvolution [Glatter (1981). J. Appl. Cryst. 14, 101-108] giving dp/dz and p, the scattering-length-density profile. The only requirement for applying the method is that the scattering-length density varies only in a limited range. In nearly all cases the approach does not require any knowledge of the chemical composition of the surface layer and consequently incorporates a certain degree of objectivity. The method gives the smoothest profile which agrees with the experimental reflectivity data. The method is tested on simulated reflectivity data for a series of different surface profiles and subsequently used for analysing experimental data on fluorocarbon amphiphiles in water and salt solutions. The tests on simulated data show that the indirect Fourier transformation gives correlation functions agreeing very well with the corresponding functions of the original profiles. It is further demonstrated that the square-root deconvolution gives reliable results for the scattering-length-density profiles.