Estudo da formação de ligação de hidrogênio em aglomerados de ácidos orgânicos e precursores de nucleação atmosférica

Abstract

The study of aerosol particles has become quite relevant in recent years as they are found to influence directly or indirectly the climate, resulting in serious consequences for ecosystems, affecting the natural cycles of rain and drought, among others. Aerosols may scatter or absorb solar radiation, altering the eenergetic balance os the atmosphere. In the present work we dedicate our efforts to study the interaction of well-known atmospheric nucleation precursors (NH3 and H2SO4) with atmospheric molecules containing sulfur, such as methanesulfonic acid (CH3SO3H) or MSA and methanesulfinic acid (CH3SO2H) or MSIA. to analyze if these molecules can contribute in the process of aerosol formation in the atmosphere. Our calculations using Density Functional Theory (DFT) and B3LYP/6 - 31 + +G(d,p) model, reveal the presence of strong hydrogen bonding in the binary MSAIMSIA- NH3/H2SO4 and ternary MSAIMSIA- (NH3 - H2SO4) clusters in the gas phase. Analysing some of the quantum-chemical molecular properties like electronic structure, binding energy and vibrational spectroscopy we conclude that among NH3 and H2SO4, MSA forms stronger binary cluster with NH3 while MSIA pre-fers H2SO4. However, among the ternary clusters, MSA- (NH3 - H2SO4) is clearly the most stabilized structure which may be helpful in aerossol formation.