Lanzilotto Valeria, Toffoli Daniele, Bernes Elisa, Stener Mauro, Viola Elisa, Cossaro Albano, Costantini Roberto, Grazioli Cesare, Totani Roberta, Fronzoni Giovanna
Department of Chemistry, Sapienza Università di Roma, P. le A. Moro 5, Roma, 00185, Italy.
IOM-CNR, Istituto Officina dei Materiali-CNR, S.S.14, Km 163.5, 34149 Trieste, Italy.
J Phys Chem A. 2022 Oct 6;126(39):6870-6881. doi: 10.1021/acs.jpca.2c04517. Epub 2022 Sep 28.
The electronic characterization of the cyanuric acid both in gas phase and when embedded within an H-bonded scheme forming a monolayer on the Au(111) surface has been performed by means of X-ray Photoelectron Spectroscopy (XPS) and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. The experimental spectra at the N, O, and C -edges have been assigned with the support of DFT calculations, and the combination between theory and experiment has allowed to us investigate the effect of the H-bonding intermolecular interaction on the spectra. In particular, the H-bond formation in the monolayer leads to a quenching of the N 1s NEXAFS resonances associated with transitions to the sigma empty orbitals localized on the N-H portion of the imide group. On the other hand, the π* empty states remain substantially unperturbed. From a computational point of view, it has been shown that the DFT-TP scheme is not able to describe the N 1s NEXAFS spectra of these systems, and the configuration mixing has to be included, through the TDDFT approach in conjunction with the range-separated XC CAM-B3LYP functional, to obtain a correct reproduction of the N 1s core spectra.
通过X射线光电子能谱（XPS）和近边X射线吸收精细结构（NEXAFS）光谱，对气相中以及嵌入在H键合体系中并在Au(111)表面形成单层的氰尿酸进行了电子表征。在DFT计算的支持下，对N、O和C边的实验光谱进行了归属，理论与实验的结合使我们能够研究H键分子间相互作用对光谱的影响。特别是，单层中H键的形成导致与向位于酰亚胺基团N-H部分的σ空轨道跃迁相关的N 1s NEXAFS共振猝灭。另一方面，π*空态基本未受干扰。从计算的角度来看，已经表明DFT-TP方案无法描述这些体系的N 1s NEXAFS光谱，必须通过结合范围分离的XC CAM-B3LYP泛函的TDDFT方法纳入构型混合，以获得N 1s核心光谱的正确再现。
