Nuclear Quantum Effects in Gas-Phase 2-Fluoroethanol

16 August 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Torsional motions along the FCCO and HOCC dihedrals lead to the five unique conformations of 2-fluoroethanol. In this work, we explore how nuclear quantum effects (NQEs) are manifest in the intramolecular landscape along these two dihedrals, through the use of path integral simulations. We have first developed a full dimensional potential energy surface using the reaction surface Hamiltonian framework. On this potential, we have carried out path integral molecular dynamics at several temperatures starting from the minimum energy well to explore structural influences of NQEs. With umbrella sampling and metadynamics simulations at 300 K and 50 K, we have explored whether NQEs have effects on the free energy landscape. Significant influences are found near the cis region of the dihedrals, which can be understood through the trends in the radii of gyration of the atomic ring polymers. We have also computed the infrared spectra at 300 K and 50 K with thermostatted ring polymer molecular dynamics simulations, which agrees well with experimental band positions.

Keywords

Nuclear Quantum Effects
Large Amplitude Motions
Free Energy Profiles
Path Integral Simulations
Potential Energy Surface

Supplementary materials

Title
Description
Actions
Title
Supporting Materials for: Nuclear Quantum effects in Gas-Phase 2-Fluoroethanol
Description
A set of additional tables and figures are provided. These include a comparison of relative energies of minima at various levels of theory, harmonic frequencies of various stationary points at the MP2/aug-cc-pVTZ level of theory, errors in the fitted internals, umbrella sampling parameters, PES quality with a quartic potential, trends of key internals from PIMD simulations, 2D (phi1, phi2) distributions from umbrella sampling simulations, radii of gyration of the ring polymers of all atoms as a function of phi1 at 300 K and 50 K from umbrella sampling simulations. The Fortran 90 code for the PES for 2FE is available here: https://github.com/arandharamrinal/2FE.
Actions

Supplementary weblinks

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.