Influence of a new potential energy surface on the rotational (de)excitation of H2O by H2 at low temperature
نویسندگان
چکیده
Aims. Using a newly determined 5D potential energy surface for H2–H2O we provide an extended and revised set of rate coefficients for de-excitation of the lowest 10 paraand 10 orthorotational levels of H2O by collisions with para-( j = 0) and ortho-H2( j = 1), for kinetic temperatures from 5 K to 20 K. Methods. Our close coupling scattering calculations involve a slightly improved set of coupled channels with respect to previous calculations. In addition, we discuss the influence of several features of this new 5D interaction on the rotational excitation cross sections. Results. The new interaction potential leads to significantly different rate coefficients for collisions with para-H2 ( j = 0). In particular the de-excitation rate coefficient for the 110 to 101 transition is increased by up to 300% at 5 K. At 20 K this increase is 75%. Rate coefficients for collisions with ortho-H2( j = 1) are modified to a lesser extent, by up to 40%. The influence of the new potential on collisions with both para-( j = 0) and ortho-H2( j = 1) is expected to become less pronounced at higher temperatures.
منابع مشابه
Rotational excitation of 20 levels of para-H2O by ortho-H2 (j2 = 1, 3, 5, 7) at high temperature
Aims. The objective is to obtain the best possible set of rotational (de)-excitation state-to-state and effective rate coefficients for temperatures up to 1500 K. State-to-state rate coefficients are presented among the 20 lowest levels of para-H2O with H2( j2 = 1) and Δ j2 = 0,+2, and among the 10 lowest levels of para-H2O with H2( j2 = 3) and Δ j2 = 0,−2. Methods. Calculations are performed w...
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