We use an amplitude of the pulse of A = 2.00 • 10 -5 a.u., the peak position of the pulse was at t p = 2.0 • 10 4 a.u. and the phase was ϕ = 0. The angular frequency of the pulse was chosen to match the excitation energy for the fundamental excitation of the symmetric bend obtained from a FVCI response calculation using the reference PES, ω = 7.2095 • 10 -3 a.u. Using the condition that the full width half maximum of the pulse equals ten times the oscillation period, the standard deviation was determined to be σ = 10 π ω √ 2 ln 2 = 3.6904 • 10 3 a.u.