Least-Squares Fitting of Multidimensional Spectra to Kubo Line-Shape Models.
Least-Squares Fitting of Multidimensional Spectra to Kubo Line-Shape Models.
复制标题
DOI：
10.1021/acs.jpcb.1c08764
复制
发表时间：
2021-11-25
期刊：
影响因子：
--
通讯作者：
Cheatum CM
中科院分区：
文献类型：
--
作者：
Robben KC;Cheatum CM
我们报告了多维光谱的最小二乘拟合对广义Kubo线形模型的有效性的综合研究，并引入了一种新的最小二乘拟合度量，称为尺度不变梯度范数（SIGN），它使高度可靠和通用的算法成为可能。与中心线-斜率法（CLS）相比，非线性模型拟合的消相参数精度提高了8 ~ 50倍，有效提高了数据采集效率1 ~ 2个数量级。CLS方法需要对非线性谱和线性谱进行序列拟合，而我们的模型拟合算法只需要非线性谱就能准确预测线性谱。我们给出了一个实验例子，其中CLS时间常数在同一系统的独立测量中相差60%，而Kubo时间常数在模型拟合中仅相差10%。这表明，模型拟合是一种比CLS方法更稳健的测量光谱扩散的方法，CLS方法更容易受到无法通过纯溶剂减法去除的结构化残余信号的影响。对CLS方法的统计分析表明，在拟合线性吸收光谱的过程中，用久保时间常数计算不确定性的传播存在根本性的疏忽。一个独立的桌面应用程序和最小二乘拟合算法的源代码是免费的，有示例线形模型和数据。我们在通用框架中编写了MATLAB源代码，用户可以在其中提供自定义线形模型。使用此应用程序，标准桌面可以在几分钟内将12参数广义Kubo模型拟合到106个数据点频谱。
We report a comprehensive study of the efficacy of least-squares fitting of multidimensional spectra to generalized Kubo line-shape models and introduce a novel least-squares fitting metric, termed the scale invariant gradient norm (SIGN), that enables a highly reliable and versatile algorithm. The precision of dephasing parameters is between 8× and 50× better for nonlinear model fitting compared to that for the centerline-slope (CLS) method, which effectively increases data acquisition efficiency by 1–2 orders of magnitude. Whereas the CLS method requires sequential fitting of both the nonlinear and linear spectra, our model fitting algorithm only requires nonlinear spectra but accurately predicts the linear spectrum. We show an experimental example in which the CLS time constants differ by 60% for independent measurements of the same system, while the Kubo time constants differ by only 10% for model fitting. This suggests that model fitting is a far more robust method of measuring spectral diffusion than the CLS method, which is more susceptible to structured residual signals that are not removable by pure solvent subtraction. Statistical analysis of the CLS method reveals a fundamental oversight in accounting for the propagation of uncertainty by Kubo time constants in the process of fitting to the linear absorption spectrum. A standalone desktop app and source code for the least-squares fitting algorithm are freely available, with example line-shape models and data. We have written the MATLAB source code in a generic framework where users may supply custom line-shape models. Using this application, a standard desktop fits a 12-parameter generalized Kubo model to a 106 data-point spectrum in a few minutes.
登录
查看更多内容
影响因子：
3.3
作者：
Dutta, Samrat;Ren, Zhe;Garrett-Roe, Sean
通讯作者：
Garrett-Roe, Sean
影响因子：
4.4
作者：
Giammanco, Chiara H.;Kramer, Patrick L.;Fayer, Michael D.
通讯作者：
Fayer, Michael D.
影响因子：
18.3
作者：
Flanagan JC;Valentine ML;Baiz CR
通讯作者：
Baiz CR
影响因子：
4.4
作者：
Falvo, Cyril
通讯作者：
Falvo, Cyril
影响因子：
4.4
作者：
Brinzer, Thomas;Berquist, Eric J.;Garrett-Roe, Sean
通讯作者：
Garrett-Roe, Sean