Collisional excitation of interstellar molecules - Water

Rate constants for excitation of water molecules by collisions with He atoms have been obtained from extensive theoretical calculations. For ortho-H2O, rates are presented for all spectroscopic levels below 1000/cm and for kinetic temperatures to 500 K; for para-H2O, levels below 300/cm and kinetic temperatures to 250 K are included. It is suggested that rates of excitation by collisions with hydrogen molecules are similar to those for He atoms.