液体束光电子能谱测量水溶液相胸苷光电子谱:综合实验误差分析

Ultraviolet Photoemission Spectra of Aqueous Thymidine by Liquid-Microjet Photoelectron Spectroscopy:A Combined Experimental Error Assessment

水溶液中的光电子发射过程易受到由弹性及非弹性电子散射、流动势和空间电荷效应引起的误差和影响,然而,直接评估这些误差中各自贡献的大小仍是一项艰巨的挑战。本文以综合实验误差的形式评估了这些误差如何影响真实的光电子动能谱,利用飞秒液体束光电子能谱技术研究不同水溶液流速和激光能量下水溶液相胸苷的紫外光电子动能(或电子结合能)谱.实验中,利用液态水的1b_(1)轨道的精确的竖直电子结合能值(11.33eV)实现对观测到的水溶液相胸苷的电子结合能谱的校准,并估算出液态水的1b_(1)轨道的精确的竖直电子结合能的综合实验误差约为200meV.在不同的流速和激光能量条件下,水溶液相胸苷阳离子基态D_(0)(π^(-1))和阳离子第一激发态D_(1)(n^(-1))的竖直电子结合能的平均综合实验误差被估计为小于3%,即误差范围在几十毫电子伏特至200meV之间.

Photoemissions from aqueous solutions are prone to elastic and inelastic electron scattering,streaming potential,and space charge effect errors;however,direct assessments of their individual contributions are still a daunting challenge.Herein,to assess how these errors in a combined experimental error manner influence on the genuine photoelectron kinetic energy(PKE)spectra,the ultraviolet PKE(or electron binding energy,eBE)spectra of aqueous thymidine at different solution flow rates and laser energies were investigated by femtosecond liquid-microjet photoelectron spectroscopy.The accurate vertical eBE value of 11.33 eV for the 1b_(1) orbital of liquid water was used to calibrate the observed eBE spectra of aqueous thymidine,and the corresponding combined experimental error for the eBE of the 1b_(1) orbital of liquid water was estimated to be about 200 meV.The average combined experimental error for the vertical eBE values of the cationic ground state D_(0)(π^(−1))and the cationic first excited state D_(1)(n^(−1))of aqueous thymidine was estimated to be less than 3%,i.e.,in the range of several tens of meV to 200 meV,depending on different flow rates and laser energies.