Toffoli D, Decleva P, Gianturco F A, Lucchese R R
The Lundbeck Foundation Center for Theoretical Chemistry, Department of Chemistry, University of Aarhus, Langelandsgade 140, DK-8000 Aarhus C, Denmark.
J Chem Phys. 2007 Dec 21;127(23):234317. doi: 10.1063/1.2813349.
Photoionization dynamics of the RNA base uracil is studied in the framework of density functional theory. The photoionization calculations take advantage of a newly developed parallel version of a multicentric approach to the calculation of the electronic continuum spectrum which uses a set of B-spline radial basis functions and a Kohn-Sham density functional Hamiltonian. Both valence and core ionizations are considered. Scattering resonances in selected single-particle ionization channels are classified by the symmetry of the resonant state and the peak energy position in the photoelectron kinetic energy scale; the present results highlight once more the site specificity of core ionization processes. We further suggest that the resonant structures previously characterized in low-energy electron collision experiments are partly shifted below threshold by the photoionization processes. A critical evaluation of the theoretical results provides a guide for future experimental work on similar biosystems.
在密度泛函理论框架下研究了RNA碱基尿嘧啶的光电离动力学。光电离计算利用了一种新开发的多中心方法的并行版本来计算电子连续谱，该方法使用一组B样条径向基函数和一个Kohn-Sham密度泛函哈密顿量。同时考虑了价电离和芯电离。通过共振态的对称性和光电子动能标度中的峰值能量位置对选定单粒子电离通道中的散射共振进行分类；目前的结果再次突出了芯电离过程的位点特异性。我们进一步表明，先前在低能电子碰撞实验中表征的共振结构在光电离过程中部分移至阈值以下。对理论结果的批判性评估为未来关于类似生物系统的实验工作提供了指导。
