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Analysis of the Electronic Structure of Aqueous Urea and Its Derivatives: A Systematic Soft X‐Ray–TD‐DFT Approach
Author(s) -
Tesch Marc F.,
Golnak Ronny,
Ehrhard Felix,
Schön Daniela,
Xiao Jie,
Atak Kaan,
Bande Annika,
Aziz Emad F.
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201601235
Subject(s) - density functional theory , chemistry , molecular orbital , electronic structure , homo/lumo , acetamide , valence (chemistry) , absorption spectroscopy , band gap , atomic physics , molecule , crystallography , computational chemistry , molecular physics , materials science , physics , optoelectronics , organic chemistry , quantum mechanics
Soft X‐ray emission (XE), absorption (XA), and resonant inelastic scattering (RIXS) experiments have been conducted at the nitrogen K‐edge of urea and its derivatives in aqueous solution and were compared with density functional theory and time‐dependent density functional theory calculations. This comprehensive study provides detailed information on the occupied and unoccupied molecular orbitals of urea, thiourea, acetamide, dimethylurea, and biuret at valence levels. By identifying the electronic transitions that contribute to the experimental spectral features, the energy gap between the highest occupied and the lowest unoccupied molecular orbital of each molecule is determined. Moreover, a theoretical approach is introduced to simulate resonant inelastic X‐ray scattering spectra by adding an extra electron to the lowest unoccupied molecular orbital, thereby mimicking the real initial state of the core‐electron absorption before the subsequent relaxation process.