For theoretically studying molecules with fluorescence in the near-infrared region, high-accuracy determination of state energy level is required for meaningful analyses since the spectra of interest are of very narrow energy range. In particular, these molecules are in many cases handled in solution; therefore, consideration of the solvation effect is essential upon calculation together with the electronic structure of the excited state. Earlier studies showed that they cannot be described with conventional methods such as PCM-TD-DFT, yielding results far from experimental data. Here, we have developed a new method by combining a solvation theory based on statistical mechanics (RISM) and a multireference perturbation theory (CASPT2) with the extension of the density matrix renormalization group reference states for calculating the photochemical properties of near-infrared molecules and have obtained higher-accuracy prediction.

中文翻译：

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RISM方法描述的电子激发溶质结合多参考微扰理论：生物成像探针的垂直激发能。

为了理论上研究在近红外区域具有荧光的分子，需要进行状态能级的高精度测定才能进行有意义的分析，因为感兴趣的光谱的能量范围非常窄。特别是，这些分子在许多情况下都是在溶液中处理的。因此，在计算时必须考虑溶剂化效应以及激发态的电子结构。较早的研究表明，它们无法用诸如PCM-TD-DFT之类的常规方法进行描述，其结果与实验数据相去甚远。这里，