Department of Physical Chemistry, Institute of Chemical Technology , Technická 5, 16628 Prague 6, Czech Republic.
J Phys Chem A. 2013 Dec 5;117(48):12868-77. doi: 10.1021/jp4098777. Epub 2013 Nov 22.
We present simulated electronic absorption spectra of isolated and solvated nitrate anion in the UV region, focusing primarily on the absorption into the first absorption band around 300 nm. This weak absorption band in this spectral region is responsible for the generation of NOx in the polar areas or OH(•) radicals in the hydrosphere. The 300 nm absorption band is symmetrically strongly forbidden and coupling of at least two vibrational modes is needed to allow the transition in the isolated nitrate anion. Further symmetry breaking is provided by solvation. In this study we model the absorption spectra of nitrate-water clusters using the combined reflection principle path integral molecular dynamics (RP-PIMD) method. Condensed phase UV spectra are modeled within a cluster-continuum model. The calculated spectra are compared with experimental bulk phase measurements and reasonable agreement is found. We also provide a benchmarking of the DFT functionals to be used for a description of the electronically excited states of solvated nitrate anion.
我们呈现了孤立和溶剂化硝酸根阴离子在紫外区域的模拟电子吸收光谱，主要关注约 300nm 处的第一吸收带的吸收。该光谱区域的这个弱吸收带负责在极性区域产生 NOx 或在水球中产生 OH(•)自由基。300nm 吸收带是对称强禁阻的，至少需要两个振动模式的耦合才能允许孤立硝酸根阴离子的跃迁。溶剂化进一步打破了对称性。在这项研究中，我们使用组合反射原理路径积分分子动力学 (RP-PIMD) 方法对硝酸盐-水团簇的吸收光谱进行建模。在团簇连续模型中模拟凝聚相紫外光谱。计算的光谱与实验的体相测量进行了比较，发现了合理的一致性。我们还为用于描述溶剂化硝酸根阴离子的电子激发态的 DFT 泛函提供了基准测试。
