Yifan Lai's research while affiliated with University of Michigan and other places

Publications (6)

Thesis
The simulation of electronically nonadiabatic dynamics and spectroscopy remains as a central challenge in computational chemistry. Amongst the reduced dynamic methods, various forms of the perturbative quantum master equation (QME) including Fermi's golden rule (FGR), Redfield equation, and Marcus theory enjoy widespread use for their efficiency in...
Article
Quantum master equations provide a general framework for describing the dynamics of electronic observables within a complex molecular system. One particular family of such equations is based on treating the off-diagonal coupling terms between electronic states as a small perturbation, within the framework of second-order perturbation theory. In thi...
Article
In this paper, we compare the ability of different quasi-classical mapping Hamiltonian methods to accurately simulate the absorption spectra of multi-excitonic molecular systems. Two distinctly different approaches for simulating absorption spectra are considered: (1) A perturbative approach, which relies on first-order perturbation theory with res...
Article
In this paper, we investigate the ability of different quasi-classical mapping Hamiltonian methods to simulate the dynamics of electronic transitions through conical intersections. The analysis is carried out within the framework of the linear vibronic coupling (LVC) model. The methods compared are the Ehrenfest method, the symmetrical quasi-classi...

Citations

... Previous findings indicate that the coupling with an optical cavity can significantly change ET rates by in-fluencing the Franck-Condon factor. 7,12,[23][24][25][29][30][31][32][48][49][50] However, prior studies did not explore how the cavity might alter the bridge-mediated (superexchange) couplings or their interferences with the direct cavitymediated interaction between D and A. We study a DBA system coupled to one radiation mode in an optical cavity. The DBA molecular HamiltonianĤ M is: ...
... Many numerical tests so far seem to indicate that the performance of the time-local form is better than that of the time non-local form for exciton and charge transfer dynamics near room temperature. However, a recent work 38 provides examples of the opposite case where the performance of time-nonlocal QME is more satisfactory than the time-local form. Therefore, further tests and comparative calculations are necessary to make more comprehensive assessment of the two approaches. ...
... troscopic observable is then typically obtained by various Fourier transforms of the associated optical response functions. Alternatively the so-called explicit light-field approach [11][12][13] can also be used to compute spectroscopic properties, by performing the dynamics associated with the coupling to a classical light field through the use of a time-dependent Hamiltonian. While this alternative approach has the advantage that it can describe processes involving strong light fields, the optical response function approach is nevertheless sufficient for and provides the simplest connection to many experiments. ...
... There are several versions of the LSC mapping dynamics by combining the choices of mapping No. 1/2 for different electronic operators and whether the resolution of identity relation is used. Here, we focus on the RI-LSC1 approach, which is also known as mLSC/ϕ 1 ϕ 1 in the literature: 15,[53][54][55][56] (1) ...
... 14,15 Due to the richness in the molecular conformations in bulk materials, multiscale modeling has been employed to incorporate these disorders in the morphology in studying the charge-transfer (CT) properties of OSC materials, 16 and we recently showed that different D/A geometries give rise to CT rate constants that can differ by orders of magnitude. 17 The classic Marcus theory is used widely for estimating the CT rate constant in a variety of condensed phase systems. 18 Traditionally, molecular dynamics (MD) simulations are used to sample molecular structures from a thermally equilibrated bulk material, and then these MD-sampled geometries of D/A molecules are used for ab initio quantum chemistry calculations to obtain energy levels and electronic couplings. ...