Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Classical calculation of radiative decay rates of hydrogenic Stark
  states   The Kepler-Coulomb problem is solved in parabolic coordinates and the Larmor
radiation problem is analyzed to complement a previous study performed for the
usual representation in spherical polar coordinates. A comparison with quantum
spontaneous decay rates shows that for azimuthal quantum number $m = 0$ states
only transitions to nearby $n-\Delta n$ principal quantum number states are
described properly by the Wentzel-Kramers-Brillouin quantized classical
motions, but that for $m > 0$ reasonable results emerge for many values of
$\Delta n$. A simple approximate expression for the lifetime of $m \ne 0$
states emerges from the semi-classical analysis.

24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci