Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electric-octupole and pure-electric-quadrupole effects in soft-x-ray
  photoemission   Second-order [O(k^2), k=omega/c] nondipole effects in soft-x-ray
photoemission are demonstrated via an experimental and theoretical study of
angular distributions of neon valence photoelectrons in the 100--1200 eV
photon-energy range. A newly derived theoretical expression for nondipolar
angular distributions characterizes the second-order effects using four new
parameters with primary contributions from pure-quadrupole and octupole-dipole
interference terms. Independent-particle calculations of these parameters
account for a significant portion of the existing discrepancy between
experiment and theory for Ne 2p first-order nondipole parameters.

17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys