Mathematics – Probability
Scientific paper
Feb 1967
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1967natur.213..694l&link_type=abstract
Nature, Volume 213, Issue 5077, pp. 694-695 (1967).
Mathematics
Probability
8
Scientific paper
IN a recent note1 Turner pointed out the confusion over the value of the Einstein A coefficient for the 2II3/2, J = 3/2, Λ-doublet transition of OH. This coefficient is required to derive the interstellar abundance of OH from the intensity of the OH absorption lines observed in radio astronomy. Turner points out an error in previous calculations which may be traced to an incorrect matrix element in equation (2-16) of Townes and Schawlow2. His own calculation, however, is also in error in some respects. The calculation of the transition probability can most conveniently be done in two steps. First the probability can be calculated for the pure Λ-doublet transition, without regard to hyperfine structure. Second, the effect of the hyperfine structure can be treated by well-known methods. The Einstein A coefficient for the Λ-doublet transition is related to the dipole matrix element μij by where |μij| is given by3 The summation is carried out only over M', since A Λ represents the probability that a molecule in one particular state M of the upper level will make a transition to any state M' of the lower level. The dipole matrix element may be related to the line strength S ij in the usual manner where μ is the permanent electric moment. S ij is identical with the familiar symmetric rotor line strength4 if K (the component of angular momentum along the molecular axis) is replaced by <Ω> ; we thus have so that With the use of the most recent molecular constants of Radford5, which lead to Ω = 1.470 and the accurate dipole moment (1.660+/-0.010 D) of Powell and Lide6, we finally obtain for the 2II3/2, J = 3/2 transition
No associations
LandOfFree
Correction of Some Erroneous Calculations of the Einstein A Coefficient for the 18 cm Transition of OH does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Correction of Some Erroneous Calculations of the Einstein A Coefficient for the 18 cm Transition of OH, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Correction of Some Erroneous Calculations of the Einstein A Coefficient for the 18 cm Transition of OH will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1807536