Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A study of H+H$_2$ and several H-bonded molecules by phaseless
  auxiliary-field quantum Monte Carlo with planewave and Gaussian basis sets   We present phaseless auxiliary-field (AF) quantum Monte Carlo (QMC)
calculations of the ground states of some hydrogen-bonded systems. These
systems were selected to test and benchmark different aspects of the new
phaseless AF QMC method. They include the transition state of H+H$_2$ near the
equilibrium geometry and in the van der Walls limit, as well as H$_2$O, OH, and
H$_2$O$_2$ molecules. Most of these systems present significant challenges for
traditional independent-particle electronic structure approaches, and many also
have exact results available. The phaseless AF QMC method is used either with a
planewave basis with pseudopotentials or with all-electron Gaussian basis sets.
For some systems, calculations are done with both to compare and characterize
the performance of AF QMC under different basis sets and different
Hubbard-Stratonovich decompositions. Excellent results are obtained using as
input single Slater determinant wave functions taken from independent-particle
calculations. Comparisons of the Gaussian based AF QMC results with exact full
configuration show that the errors from controlling the phase problem with the
phaseless approximation are small. At the large basis-size limit, the AF QMC
results using both types of basis sets are in good agreement with each other
and with experimental values.

13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph