In the following set of simulations we consider three cases which we label the overdamped (fastest dissipation rate), intermediate and underdamped (slowest dissipation rate). We note that although the mathematical form of the bath is underdamped, all cases can be constructed by consideration of the damping parameters. In all simulated 2D spectra we use a ground and excited state separation of ωeg = 10 000 cm -1 . The vibrational mode of the system is ω0 = 500 cm -1 , where the (dimensionless) displacement of the excited state potential is ∆ 0 = 1.09 giving a reorganisation energy of λ = 300 cm -1 . The parameters in the case of the overdamped regime (ODR) are γ 1 = 1 750 cm -1 , and γ 2 = 2 500 cm -1 such that Λ = 100 cm -1 . The intermediate dissipation rate (IDR) case has γ 1 = 100 cm -1 , and γ 2 = 2 500 cm -1 such that Λ = 100 cm -1 . The underdamped regime (UDR) case has γ 1 = 100 cm -1 , and γ 2 = 300 cm -1 . In all cases the bath coupling and vibrational mode frequency are: