Electron Photoemission Spectra of Molecular Structure and Quantum Fluctuation Theorem

Abstract

The possibility of applying the quantum fluctuation theorem (QFT) to deep-lying electron orbitals in experimental atomic photon ↔ electron transition cross-section spectra is considered. Such spectra can only be obtained as a function of the difference between the experimentally measured excitation energy and final state energy. It is shown that spectra in this function do not satisfy the QFT. An assumption is made that the cross-section spectra are changed by screening of the transition excitations by an ensemble of neighboring electrons (orbitals). A screening coefficient that is constant across the observed spectrum and accounts for the reduction of the excitation energy (cross section) to the elementary starting state due to the screening is introduced into the QFT relations for such transition cross-sections. The spectra satisfy the QFT relations if screening is considered. Calculations using these assumptions are applied to electron x-ray photoemission spectra, inverse x-ray photoemission spectra, and electron energy loss (absorption) spectra. It is found that screening weakens the non-valence atomic orbital transition cross section by an order of magnitude or more, but only by several times for the outer (valence) ones. It was found that identification of the purely electronic transition position using QFT relations from the observed spectrum depended on the screening coefficient.