Department of Physics, Imperial College London, London SW7 2AZ, UK.
Phys Chem Chem Phys. 2022 Sep 14;24(35):20776-20787. doi: 10.1039/d2cp02365b.
Cumulant mapping employs a statistical reconstruction of the whole by sampling its parts. The theory developed in this work formalises and extends methods of 'multi-fold' or 'multi-dimensional' covariance mapping. Explicit formulae have been derived for the expected values of up to the 6th cumulant and the variance has been calculated for up to the 4th cumulant. A method of extending these formulae to higher cumulants has been described. The formulae take into account reduced fragment detection efficiency and a background from uncorrelated events. Number of samples needed for suppressing the statistical noise to a required level can be estimated using Matlab code included in Supplemental Material. The theory can be used to assess the experimental feasibility of studying molecular fragmentations induced by femtosecond or X-ray free-electron lasers. It is also relevant for extending the conventional mass spectrometry of biomolecules to multiple dimensions.
累积映射通过对部分进行采样来对整体进行统计重建。本工作中发展的理论形式化并扩展了“多倍”或“多维”协方差映射的方法。已经推导出了最高到第 6 阶累积量的期望值的显式公式，并且已经计算了最高到第 4 阶累积量的方差。描述了将这些公式扩展到更高阶累积量的方法。这些公式考虑了降低的片段检测效率和来自不相关事件的背景。可以使用随附材料中的 Matlab 代码来估计抑制所需水平的统计噪声所需的样本数量。该理论可用于评估使用飞秒或 X 射线自由电子激光研究分子碎裂的实验可行性。它也与将生物分子的常规质谱法扩展到多个维度相关。
