Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theory of the singlet exciton yield in light-emitting polymers   This paper presents a possible explanation for the enhanced singlet exciton
yield in light emitting polymers. We propose a theory of electron-hole
recombination via inter-molecular inter-conversion from inter-molecular weakly
bound polaron pairs (or charge-transfer excitons) to intra-molecular excitons.
This theory is applicable to parallel polymer chains. A crucial aspect of the
theory is that both the intra-molecular and inter-molecular excitons are
effective-particles, which are described by both a relative-particle
wavefunction and a center-of-mass wavefunction. This implies two electronic
selection rules. (1) The parity of the relative-particle wavefunction implies
that inter-conversion occurs from the even parity inter-molecular
charge-transfer excitons to the strongly bound intra-molecular excitons. (2)
The orthonormality of the center-of-mass wavefunctions ensures that
inter-conversion occurs from the charge-transfer excitons to the lowest branch
of the strongly bound exciton families, and not to higher lying members of
these families. The inter-conversion is then predominately a multi-phonon
process, determined by the Franck-Condon factors. These factors are
exponentially smaller for the triplet manifold than the singlet manifold
because of the large exchange energy.

2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc