(color online) Simulated longitudinal velocity distribution of the ND₃ molecular beam after the bend filter (square points). The dashed line is a fitted one and the corresponding beam has a most probable velocity of 80 m·s⁻¹ with a velocity spread of 73 m·s⁻¹. Simulated longitudinal velocity distribution of the beam after 20 bunching stages (dots). It is centered around 100 m·s⁻¹, with a velocity spread of 8.9 m·s⁻¹. The dashed line is the fitting result.