Open AccessThe radiative association of Si and N atoms, C and O atoms, and C atoms and S + ions
Author(s) -
Singh P. D.,
Sanzovo G. C.,
Borin A. C.,
Ornellas F. R.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2958.2008.06311.x-i1
Subject(s) - radiative transfer , physics , atomic physics , ion , range (aeronautics) , einstein coefficients , potential energy , order (exchange) , spectral line , quantum mechanics , materials science , finance , economics , composite material
Potential energy curves for the SiN.X 2 Σ + and A 2 Π i electronic states, and the SiN(A 2 Π i ‐‐X 2 Σ + ) transition moment function (TMF) are obtained at the MRCI level of theory, with a SA‐CASSCF zero‐order wavefunction. These potential energy curves and TMF are used to compute radiative association rate coefficients of Si and N atoms for temperatures in the range 300‐‐14 700 K. Rate coefficients for radiative association of carbon and oxygen atoms for the formation of CO, and carbon atoms and sulphur ions for the formation of CS + , are also calculated for temperatures in the range 300‐‐14 700 K. These radiative association rate coefficients ( k ) are fitted to the standard equation 1where A=2.02×10 −19 cm 3 s −1 , α=0.029 and β=83.9 for the SiN molecule. The corresponding values for the CO molecule are 3.09×10 −17 cm 3 s −1 , 0.325 and 1629, and those for the CS + ion are 2.01×10 −18 cm 3 s −1 , 0.066 and 300.9. Radiative association of C and O atoms occurs with emissions of the first overtone band at 2.3 μm and the fundamental band at 4.6 μm found in the ejecta of Supernova 1987A and novae.