Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Time-dependent N-electron valence perturbation theory with matrix
  product state reference wavefunctions for large active spaces and basis sets:
  Applications to the chromium dimer and all-trans polyenes   In earlier work [J. Chem. Phys. 144, 064102 (2016)], we introduced a
time-dependent formulation of the second-order N-electron valence perturbation
theory (t-NEVPT2) which (i) had a lower computational scaling than the usual
internally-contracted perturbation formulation, and (ii) yielded the fully
uncontracted NEVPT2 energy. Here, we present a combination of t-NEVPT2 with a
matrix product state (MPS) reference wavefunction (t-MPS-NEVPT2) that allows to
compute uncontracted dynamic correlation energies for large active spaces and
basis sets, using the time-dependent density matrix renormalization group
(td-DMRG) algorithm. In addition, we report a low-scaling MPS-based
implementation of strongly-contracted NEVPT2 (sc-MPS-NEVPT2) that avoids
computation of the four-particle reduced density matrix. We use these new
methods to compute the dissociation energy of the chromium dimer and to study
the low-lying excited states in all-trans polyenes (C$_4$H$_6$ to
C$_{24}$H$_{26}$), incorporating dynamic correlation for reference
wavefunctions with up to 24 active electrons and orbitals.

36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
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The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess