We present an exhaustive computational study on the effect of high pressure on normal alcohols with alkyl chains with lengths of three-to-eight carbon atoms. 1-Propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol were studied by using classical molecular dynamics simulations and applying pressures in the range of 1 to 10 bar. The results of our calculations show that high-pressure values affect the structure significantly. In particular, we have observed a marked difference in behavior for alcohols with chain lengths below six and those with more than six or seven carbon atoms, with hexanol and heptanol being boundary cases. We have named the model with the most shrunk alkyl chains as the Asclepius form inspired by the Rod of Asclepius, the universally known symbol of medicine, in which a snake is coiled around a rod.

In the present letter, we investigate the double proton transfer (DPT) tautomerization process in guanine−cytosine (GC) DNA base pairs. In particular, we study the influence of the biological environment on the mechanism, the kinetics and thermodynamics of such DPT. To this end, we present a molecular dynamics (MD) study in the tight-binding density functional theory framework, and compare the reactivity of the isolated GC dimer with that of the same dimer embedded in a small DNA structure. The impact of nuclear quantum effects (NQEs) is also evaluated using Path Integral based MD. Results show that in the isolated dimer, the DPT occurs via a concerted mechanism, while in the model biological environment, it turns into a stepwise process going through an intermediate structure. One of the water molecules in the vicinity of the proton transfer sites plays an important role as it changes H-bond pattern during the DPT reaction. The inclusion of NQEs has the effect of speeding up the tautomeric-to-canonical reaction, reflecting the destabilization of both the tautomeric and intermediate forms.

We study the double proton transfer (DPT) tautomerization process in Guanine- Cytosine (GC) DNA base pairs. In particular, we investigate the influence of the biological environment on the mechanism, the kinetics and thermodynamics of such DPT. To this end, we present a molecular dynamics study in the tight-binding density functional theory framework, and compare the reactivity of the GC dimer in the gas phase with that of the same dimer embedded in a small DNA structure. The impact of nuclear quantum effects is also evaluated using the Ring Polymer Molecular Dynamics. Results show that in the isolated dimer, the DPT occurs via a concerted mechanism, while in the model biological environment, it turns into a step-wise process going through an intermediate structure. One of the water molecules in the vicinity of the proton transfer sites plays an important role as it changes H-bond pattern during the DPT reaction.

In the present work, we investigate how nuclear quantum effects modify the temperature dependent rate constants and, consequently, the activation energies in unimolecular reactions. In the reactions under study, nuclear...