« Previous AbstractDifferential expression of odorant receptor genes involved in the sexual isolation of two Heliothis moths    Next AbstractOdor analysis of decomposing buried human remains »

J Phys Chem B

Title:		Can Path Integral Molecular Dynamics Make a Good Approximation for Vapor Pressure Isotope Effects Prediction for Organic Solvents? A Comparison to ONIOM QM/MM and QM Cluster Calculation
Author(s):		Vasquez L; Rostkowski M; Gelman F; Dybala-Defratyka A;
Address:		"Institute of Applied Radiation Chemistry, Faculty of Chemistry , Lodz University of Technology , Zeromskiego 116 , 90-924 Lodz , Poland. Geological Survey of Israel , Malkhei Israel Street 30 , 95501 Jerusalem , Israel"
Journal Title:		J Phys Chem B
Year:		2018
Volume:		20180716
Issue:		29
Page Number:		7353 - 7364
DOI:		10.1021/acs.jpcb.8b03444
ISSN/ISBN:		1520-5207 (Electronic) 1520-5207 (Linking)
Abstract:		"Isotopic fractionation of volatile organic compounds (VOCs), which are under strict measures of control because of their potential harm to the environment and humans, has an important ecological aspect, as the isotopic composition of compounds may depend on the conditions in which such compounds are distributed in Nature. Therefore, detailed knowledge on isotopic fractionation, not only experimental but also based on theoretical models, is crucial to follow conditions and pathways within which these contaminants are spread throughout the ecosystems. In this work, we present carbon and, for the first time, bromine vapor pressure isotope effect (VPIE) on the evaporation process from pure-phase systems-dibromomethane and bromobenzene, the representatives of aliphatic and aromatic brominated VOCs. We combine isotope effects measurements with their theoretical prediction using three computational techniques, namely path integral molecular dynamics, QM cluster, and hybrid ONIOM models. While evaporation of both compounds resulted in normal bromine VPIEs, the difference in the direction of carbon isotopic fractionation is observed for the aliphatic and aromatic compounds, where VPIEs are inverse and normal, respectively. Even though theoretical models tested here turned out to be insufficient for quantitative agreement with the experimental values, cluster electronic structure calculations, as well as two-layer ONIOM computations, provided better reproduction of experimental trends"
Keywords:
Notes:		"PubMed-not-MEDLINEVasquez, Luis Rostkowski, Michal Gelman, Faina Dybala-Defratyka, Agnieszka eng Research Support, Non-U.S. Gov't 2018/07/03 J Phys Chem B. 2018 Jul 26; 122(29):7353-7364. doi: 10.1021/acs.jpcb.8b03444. Epub 2018 Jul 16"