Internal conversion rate constant calculations considering Duschinsky, anharmonic and Herzberg–Teller effects

Abstract

A novel method for calculating rate constants for internal conversion (kIC) that simultaneously accounts for Duschinsky, anharmonic and Herzberg–Teller effects has been developed and implemented.

First-Principles Calculations of Excited-State Decay Rate Constants in Organic Fluorophores

“…In more recent work, the same group investigated the impact of Duschinsky, HT, and anharmonic effects on k IC on a series of planar rigid organic fluorophores. 66 They found that the anharmonicities have more impact on k IC , followed by HT effects and Duschinsky contributions, respectively. This highlights that both anharmonicities and HT contributions should ideally be taken into account to obtain accurate k IC estimates.…”

Influence of plasmons on the luminescence properties of solvatochromic merocyanine dyes with different solvatochromism

“…The k IC rate constants were calculated using the algorithm described in ref. 96:where the summation considers the energy conservation condition andHere, and are the nonadiabatic coupling matrix elements (NACME) of first and second order, respectively; M v is the mass of the v th atom, and L vqj are coefficients of the linear relation between the Cartesian ( R ) and the normal coordinates ( Q ): ; the y j is the Huang–Rhys factor of the j th promotive mode; E if is the energy gap between initial and final states, and n j and ω j are the excitation number and the energy of the j :th mode, respectively; b j and t j are the matrix elements of Q j and d/d Q j , respectively, between the nuclear functions of the initial and final electronic states, which are calculated by considering anharmonic effects using the Morse potential. 75,96…”

“…Accurate intramolecular radiationless rate constants are calculated using the theoretical models and quantum chemical methods described in ref. 65, 73–75, 94 and 96.…”

Effect of choosing coordinate systems on computationally predicting nonradiative transition rates of flexible thermally activated delayed fluorescence molecules

“…To mitigate such failure, it was shown that the Morse potential can be employed to account for anharmonicity with demonstrations on actual molecular systems. [36][37][38][39] However, it should be noted that Morse potentials depend on empirical parameters, which may induce some degree of uncertainty especially for polyatomic systems. Thus, we will not discuss their usage within this account for OLED molecules.…”

“…Specifically, the analytic formulation heavily relies on the harmonic oscillator approximation for molecular vibrations, which inevitably fails at large distortions. To mitigate such failure, it was shown that the Morse potential can be employed to account for anharmonicity with demonstrations on actual molecular systems 36–39 . However, it should be noted that Morse potentials depend on empirical parameters, which may induce some degree of uncertainty especially for polyatomic systems.…”