The dynamics of bulk liquid
para
-cresol
from 340–390
K was probed using a tandem quasielastic neutron scattering (QENS)
and molecular dynamics (MD) approach, due to its relevance as a simple
model component of lignin pyrolysis oil. QENS experiments observed
both translational jump diffusion and isotropic rotation, with diffusion
coefficients ranging from 10.1 to 28.6 × 10
–10
m
2
s
–1
and rotational rates from 5.7
to 9.2 × 10
10
s
–1
. The associated
activation energies were 22.7 ± 0.6 and 10.1 ± 1.2 kJmol
–1
for the two different dynamics. MD simulations applying
two different force field models (OPLS3 and OPLS2005) gave values
close to the experimental diffusion coefficients and rotational rates
obtained upon calculating the incoherent dynamic structure factor
from the simulations over the same time scale probed by the QENS spectrometer.
The simulations gave resulting jump diffusion coefficients that were
slower by factors of 2.0 and 3.8 and rates of rotation that were slower
by factors of 1.2 and 1.6. Comparing the two force field sets, the
OPLS3 model showed slower rates of dynamics likely due to a higher
molecular polarity, leading to greater quantities and strengths of
hydrogen bonding.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.