Collisional excitation of NH3 by atomic and molecular hydrogen

摘要: We report extensive theoretical calculations on the rotation-inversion excitation of interstellar ammonia (NH3) due to collisions with atomic and molecular hydrogen (both para- ortho-H2). Close-coupling are performed for total energies in range 1-2000 cm-1 rotational cross sections obtained all transitions among lowest 17 34 levels ortho- para-NH3, respectively. Rate coefficients deduced kinetic temperatures up 200 K. Propensity rules three colliding partners discussed we also compare new results previous spherically symmetrical He para-H2 projectiles. Significant differences found between different sets calculations. Finally, test impact rate calibration thermometer. find that curve is only weakly sensitive partner confirm thermometer robust.