School of Chemistry, National University of Ireland, Galway, Ireland.
J Phys Chem A. 2010 Sep 23;114(37):10234-42. doi: 10.1021/jp104127r.
Computing accurate absorption spectra of riboflavin (RBF) has proven a difficult task for computational chemistry. Time-dependent density functional theory have herein been employed using a wide range of recent range-separated and hybrid meta functionals to investigate ultraviolet and visible spectra of RBF to determine if any progress has been made through recent developments. It is concluded that B3LYP and PBE0 perform the best throughout the entire test set. However, since all methods deviate from experimental results by at least 40 nm when computing the spectra in vacuum, two approaches to describe aqueous solution are implemented together with the MPWB1K, B3LYP, and PBE0 functionals: implicitly using integral equation formulation of the polarized continuum model (minor improvement) and explicitly through molecular dynamics (MD) simulations of the molecule embedded in a water cluster whereafter snapshots of RBF-water clusters are extracted and time-dependent density functional theory calculations performed. The resulting averaged spectra from the MD-simulated clusters show a constant blue-shift for all peaks by ∼20 nm compared to experimental data at the TD-B3LYP/6-31+G(d,p) level.
计算核黄素（RBF）的精确吸收光谱对于计算化学来说一直是一项艰巨的任务。本文使用多种最新的区间分离和混合泛函的时间相关密度泛函理论来研究 RBF 的紫外和可见光谱，以确定最近的发展是否取得了进展。结果表明，B3LYP 和 PBE0 在整个测试集中表现最好。然而，由于所有方法在计算真空光谱时至少偏离实验结果 40nm，因此采用两种方法来描述水溶液：与 MPWB1K、B3LYP 和 PBE0 泛函一起使用介电常数方程形式的极化连续体模型（略有改进）和通过分子动力学（MD）模拟嵌入在水分子簇中的分子来显式描述，此后提取 RBF-水分子簇的快照并进行时间相关密度泛函理论计算。与 TD-B3LYP/6-31+G(d,p) 水平的实验数据相比，从 MD 模拟簇中得出的平均光谱显示所有峰的蓝移常数均为 20nm 左右。
