Ultraviolet photoemission spectra of aqueous thymidine by liquid-microjet photoelectron spectroscopy: A combined experimental error assessment

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 lbi 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 lbi 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(pi(-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.