Hyperfine excitation of CN by para- and ortho-H2
Among the interstellar molecules, the CN radical is of particular interest since it is a good probe of cold dark molecular clouds, and especially prestellar cores. Modelling of CN emission spectra from these dense molecular clouds requires the calculation of rate coefficients for excitation by colli...
| Published in: | Monthly Notices of the Royal Astronomical Society Vol. 446. P. L21-L25 |
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| Format: | Article |
| Language: | English |
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| Online Access: | http://vital.lib.tsu.ru/vital/access/manager/Repository/vtls:000525178 Перейти в каталог НБ ТГУ |
| Summary: | Among the interstellar molecules, the CN radical is of particular interest since it is a good probe of cold dark molecular clouds, and especially prestellar cores. Modelling of CN emission spectra from these dense molecular clouds requires the calculation of rate coefficients for excitation by collisions with the most abundant species. We calculate fine- and hyperfinestructure-resolved excitation rate coefficients of CN(X2+) by para- and ortho-H2. The calculations are based on a new potential energy surface obtained recently from highly correlated ab initio calculations. State-to-state rate coefficients between fine and hyperfine levels of CN were calculated for low temperatures ranging from 5 to 100 K. The new results are compared to available CN rate coefficients. Significant differences are found between the different sets of rate coefficients. This comparison shows that the new CN-H2 rate coefficients have to be used for observations interpretations. We expect that their use will help significantly to have a new insight into the physical conditions of prestellar cores. |
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| Bibliography: | Библиогр.: с. L25 |
| ISSN: | 0035-8711 |