On vibrational excitations of interstellar molecules

Recent calculations of collisional vibrational excitations of interstellar molecules assumed a strong suppression of delta v greater than one transitions. However, a large body of evidence suggests that collisions may actually induce large changes in v. Excitation calculations presented here show that the outcome depends strongly on the form of the cross sections used. The results of calculations of collisional excitations therefore cannot be considered reliable before the issue of the cross sections is settled more definitely.