Values of the Einstein A Coefficients for the Λ Doublet Transitions of the Ground State of OH.

Abstract

view Abstract Citations (1) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Values of the Einstein A Coefficients for the Λ Doublet Transitions of the Ground State of OH. Goss, W. Miller ; Weaver, Harold Abstract In order to calculate abundances of OH from the four lines at 18 Cm, the Einstein A's are necessary. A recalculation of these quantities for the A doublet transitions arising from the ground state (2113/2) of OH has been made. The expression for the dipole matrix element as reported by Dousmanis, Sanders, and Townes (Phys. Rev. 100, 1735, 1955) is incorrect. The correct formulation has been given by Meyer (unpublished thesis, University of California, Berkeley, 1961). The Dousmanis, Sanders, and Townes expression must be multiplied by (2J+ 1) /J. This factor is 2.67 for the ground state of OH (J=3/2). Using recent experimental data on the dipole moment and the fine structure interaction constant of OH, the dipole matrix element is calculated for the case of intermediate coupling between Hund's cases a and b. The resultant A's are: 0.1614x 10-11 sec-', 0.8895 x 10-" sec-1, 0.9640x 10-" sec-1, and 0.1177x 10-" sec-1 for the 1612, 1665, 1667, and 1720 Mc/sec lines, respectively. The A value computed here for the 1667 Mc/sec line differs significantly from the value (2.66 X 10-" sec-1) given by Barrett (IEEE Trans. on Military Electron. MIL-8, 156, 1964). OH abundances computed with this earlier A value must be increased in the ratio 2.66x 10-"/0.964x 10-"=2.76. Publication: The Astronomical Journal Pub Date: 1966 DOI: 10.1086/110162 Bibcode: 1966AJ.....71T.162G full text sources ADS |