c CCLRC
Section 3.5
The conserved quantity is
H
N
T
= H
NVE
+
q
mass
(t)
2
2
+
p
mass
Tr[ ·
T
]
2
+ P
ext
V (t) + (f + 3
2
) k
B
T
ext
t
o
(s)ds . (3.87)
The VV and LFV flavours of the non-isotropic Nos´e-Hoover barostat (and thermostat) are imple-
mented in the DL POLY 3 routines nst h1 vv and nst h1 lfv respectively.
3.5.4
Martyna-Tuckerman-Klein Barostat
DL POLY 3 includes the Martyna-Tuckerman-Klein (MTK) interpretation of the VV flavoured
Hoover algorithms [
] for isotropic and anisotropic cell fluctuations in which the equations of
motion are slightly modified to those for the coupled Nos´e-Hoover thermostat and barostat so
that to exclude the use of R
0
in the position scaling due to the barostat. In this way they are
proved to generate ensembles that conserve the phase space volume and thus have well defined
conserved quantities even in presence of forces external to the system [
for Nos´e-Hoover NPT and NT ensembles.
The NPT and NT versions of the MTK ensemble are implemented in the DL POLY 3 routines
npt m1 vv and nst m1 vv.
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