Analysis of the Electronic Structure of Aqueous Urea and Its Derivatives: A Systematic Soft X‐Ray–TD‐DFT Approach1. Issue 34 (15th July 2016)

• Record Type: Journal Article
• Authors: Tesch, Marc F.; Golnak, Ronny; Ehrhard, Felix; Schön, Daniela; Xiao, Jie; Atak, Kaan; Bande, Annika; Aziz, Emad F.
• Is Part Of: Chemistry. Volume 22:Issue 34(2016)
• Page Start: 12040
• Page End: 12049
• Publication Date: 2016-07-15
• Subjects: density functional calculations -- frontier orbitals -- liquids -- ureas -- X-ray spectroscopy; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201601235
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: 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. Abstract : The ins and out : X‐ray absorption and X‐ray emission spectroscopies were conducted at the nitrogen K‐edge of aqueous urea and its derivatives. These techniques allow the analysis of the unoccupied and occupied molecular orbitals (see scheme). The experimental results were compared to ab initio calculations to obtain a comprehensive picture of the electronic structure of the studied molecules. Furthermore, a new theoretical approach is presented to interpret resonant inelastic X‐ray scattering spectra.