Green James A, Jouybari Martha Yaghoubi, Aranda Daniel, Improta Roberto, Santoro Fabrizio
CNR-Consiglio Nazionale delle Ricerche, Istituto di Biostrutture e Bioimmagini (IBB-CNR), Via Mezzocannone 16, I-80136 Napoli, Italy.
CNR-Consiglio Nazionale Delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area Della Ricerca, Via G. Moruzzi 1, I-56124 Pisa, Italy.
Molecules. 2021 Mar 20;26(6):1743. doi: 10.3390/molecules26061743.
We have recently proposed a protocol for Quantum Dynamics (QD) calculations, which is based on a parameterisation of Linear Vibronic Coupling (LVC) Hamiltonians with Time Dependent (TD) Density Functional Theory (TD-DFT), and exploits the latest developments in multiconfigurational TD-Hartree methods for an effective wave packet propagation. In this contribution we explore the potentialities of this approach to compute nonadiabatic vibronic spectra and ultrafast dynamics, by applying it to the five nucleobases present in DNA and RNA. For all of them we computed the absorption spectra and the dynamics of ultrafast internal conversion (100 fs timescale), fully coupling the first 2-3 bright states and all the close by dark states, for a total of 6-9 states, and including all the normal coordinates. We adopted two different functionals, CAM-B3LYP and PBE0, and tested the effect of the basis set. Computed spectra are in good agreement with the available experimental data, remarkably improving over pure electronic computations, but also with respect to vibronic spectra obtained neglecting inter-state couplings. Our QD simulations indicate an effective population transfer from the lowest energy bright excited states to the close-lying dark excited states for uracil, thymine and adenine. Dynamics from higher-energy states show an ultrafast depopulation toward the more stable ones. The proposed protocol is sufficiently general and automatic to promise to become useful for widespread applications.
我们最近提出了一种用于量子动力学（QD）计算的协议，该协议基于用含时密度泛函理论（TD-DFT）对线性振子-电子耦合（LVC）哈密顿量进行参数化，并利用多组态含时哈特里方法的最新进展来实现有效的波包传播。在本论文中，我们通过将该方法应用于DNA和RNA中存在的五种核碱基，探索了其计算非绝热振子-电子光谱和超快动力学的潜力。对于所有这些核碱基，我们计算了吸收光谱以及超快内转换（100飞秒时间尺度）的动力学，完全耦合了前2 - 3个明亮态和所有相邻的暗态，总共6 - 9个态，并包括了所有的正则坐标。我们采用了两种不同的泛函，CAM-B3LYP和PBE0，并测试了基组的影响。计算得到的光谱与现有的实验数据吻合良好，与纯电子计算相比有显著改进，而且相对于忽略态间耦合得到的振子-电子光谱也有改进。我们的QD模拟表明，对于尿嘧啶、胸腺嘧啶和腺嘌呤，存在从最低能量明亮激发态到相邻暗激发态的有效布居转移。来自高能态的动力学显示向更稳定态的超快布居减少。所提出的协议足够通用且自动化，有望在广泛的应用中发挥作用。
