Comparison among several vibronic coupling methods

Revisiting the Spectrum of Co(CN)63–: The Role of Correlation, Solvation, and Vibronic and Spin–Orbit Couplings

“…A similar procedure was done in a previous work. 70 The reference value for band integrals was the one obtained with CASSCF/NEVPT2 with γ = 30 nm and σ = 0.075 in order to have the best possible agreement with the experimental spectrum. Although CASSCF/NEVPT2 is the reference, its high computational cost motivates us to simulate the spectrum with other methods.…”

“…The standard deviation (σ) used in each method were chosen considering the band intensity to be equal to the sum of OOSs of the degenerate transitions and γ were chosen in order to have the same band integrals. A similar procedure was done in a previous work . The reference value for band integrals was the one obtained with CASSCF/NEVPT2 with γ = 30 nm and σ = 0.075 in order to have the best possible agreement with the experimental spectrum.…”

“…An investigation of vibronic effects was carried out using the direct vibronic coupling (DVC) method. − Briefly, on this method, the total wave function is written as product of the vibrational and electronic wave functions. The intensity of an excitation from the lowest vibrational level of the ground electronic state to the vibrational level (ν) of the excited electronic state k can be obtained by the optical oscillator strength (OOS), which is given by f false( E false) 00 → k ν = 2 3 normalΔ E 00 → k ν g k | ⟨ χ k ν | M k 0 false| χ 00 false⟩ false| 2 where the transition dipole moment is M k 0 = ∑ i = 1 false⟨ ψ k ( r , Q ) | r i | ψ 0 ( r , Q ) false⟩ …”

On the short and long phosphorescence lifetimes of aromatic carbonyls

“…Both molecules have 3 * T1 minima; direct SOC should not contribute, as we can see in Eq. (20). The vertical contributions are nearly null for all three terms in Figure 7, explaining the 272 ms and 114 ms long lifetimes of MoBA and DMBA, respectively.…”

“…Different methods are available to incorporate vibronic couplings into the simulations, such as the nuclear ensemble approach (NEA) [16], direct vibronic coupling [17], adiabatic Hessian [18], and vertical gradient [19]. Torres and co-authors recently compared them, and the interested reader may know more about the pros and cons of each one in their paper [20]. We particularly favor NEA, which we have been developing and applying for many years to simulate different spectrum types and generate initial conditions for dynamics [16,21,22].…”