Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ab initio Molecular Dynamics Study of Glycine Intramolecular Proton
  Transfer in Water   We use ab initio molecular dynamics simulations to quantify structural and
thermodynamic properties of a model proton transfer reaction that converts a
neutral glycine molecule, stable in the gas phase, to the zwitterion that
predominates in aqueous solution. We compute the potential of mean force
associated with the direct intramolecular proton transfer event in glycine.
Structural analyses show that the average hydration number Nw of glycine is not
constant along the reaction coordinate, but rather progresses from Nw=5 in the
neutral molecule to Nw=8 for the zwitterion. We report the free energy
difference between the neutral and charged glycine molecules, and the free
energy barrier to proton transfer. Finally, we identify approximations inherent
in our method and estimate corresponding corrections to our reported
thermodynamic predictions.

15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
1
The categories of this paper are: cs
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph