Shi and co-workers took the Plotnikov-Robinson-Jortner model, and looked to develop a model to allow for high thoroughput virtual screening for material candidates. For such a purpose, the focus would be on speed rather than accuracy, with a focus only on capturing trends . To allow for this, they used a simplified form of Equation by replacing the vibronic coupling with an effective coupling of a linear combination of all non-adiabatic couplings for all non-zero normal modes, cast as :