Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Subsystem constraints in variational second order density matrix
  optimization: curing the dissociative behavior   A previous study of diatomic molecules revealed that variational second-order
density matrix theory has serious problems in the dissociation limit when the
N-representability is imposed at the level of the usual two-index (P, Q, G) or
even three-index (T1, T2) conditions [H. van Aggelen et al., Phys. Chem. Chem.
Phys. 11, 5558 (2009)]. Heteronuclear molecules tend to dissociate into
fractionally charged atoms. In this paper we introduce a general class of
N-representability conditions, called subsystem constraints, and show that they
cure the dissociation problem at little additional computational cost. As a
numerical example the singlet potential energy surface of BeB+ is studied. The
extension to polyatomic molecules, where more subsystem choices can be
identified, is also discussed.

19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin