PRACTICAL REGULARIZATION METHODS FOR ANALYSIS OF EXAFS SPECTRA: DATA ANALYSIS

X射线吸收精细结构XAFS是一种强有力的技术， 探测生物体内金属原子的局部环境 大分子 这些金属原子常见于 例如，酶，并且对于它们的功能是必不可少的。 分析 XAFS数据是一项耗时的活动， 经验做正确的，限制了适用范围的 法 为了改善这种情况，我们已申请 反问题的Tikhonov正则化方法 直接重建原子的分布， 诉诸于对它的形状的特别假设。 该程序 在测试用例中表现出色，解决了 通常无法解析，并且由于该方法是线性的，因此没有 局部极小值的困难。 正则化过程可以是 在普通的台式电脑上完成， 令人满意地重建了几个原子的分布 类型同时 在测试用例中，我们发现该方法远 优于传统方法。 我们目前正在努力， 将该方法推广到多次散射。 这项工作代表 这是一个很有前途的发展方向，可以预期 在未来的研究中产生更可靠的结果和解释。

X-ray absorption fine structure XAFS is a powerful technique for probing the local environment of metal atoms in biological macromolecules. These metal atoms are common in the active sites of enzymes, for example, and are essential for their function. Analysis of XAFS data is a time consuming activity that requires extensive experience to do correctly, limiting the range of applicability of the technique. In an attempt to improve this situation, we have applied the approach of Tikhonov regularization to solve the inverse problem of reconstructing the distribution of atoms directly, without resorting to ad-hoc assumptions about its shape. The procedure has performed excellently in test cases, resolving features that are normally unresolvable, and since the method is linear, there is no difficulty with local minima. The regularization procedure can be done on ordinary desktop computers in minutes, and we have satisfactorily reconstructed the distributions for several atomic types simultaneously. In test cases we have found the method far outperforms traditional approaches. We are presently working to generalize this method for multiple scattering. This work represents a promising development towards direct methods which can be expected to yield more reliable results and interpretations in future studies.