Microstructure of neat alcohols: a molecular dynamics study

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Materials Science

Background:

• Understanding liquid microstructure is crucial for predicting macroscopic properties.
• Alcohols exhibit complex hydrogen-bonding networks influencing their structure.
• Previous studies have explored alcohol structures, but detailed microstructural analysis remains an active research area.

Purpose of the Study:

• To investigate and compare the detailed microstructure of neat methanol and tert-butanol.
• To identify appropriate statistical methods for characterizing liquid microstructures.
• To analyze the presence and nature of local microheterogeneity in these alcohols.

Main Methods:

• Employed molecular dynamics simulations to model neat methanol and tert-butanol.
• Utilized site-site radial distribution functions and structure factors for analysis.
• Applied an effective local one-body density function to complement structural data.

Main Results:

• Methanol exhibits a weakly associated liquid structure with diverse chainlike patterns (open and closed).
• Tert-butanol displays a highly associated liquid structure forming prominent micellelike clusters.
• Both alcohols demonstrate stable local microheterogeneity within their disordered phases.

Conclusions:

• Site-site radial distribution functions, structure factors, and local density functions are effective tools for characterizing liquid microstructure.
• Significant differences in association and clustering exist between methanol and tert-butanol.
• The observed microheterogeneity in alcohols contrasts with the homogeneous structure of water, despite water's stronger hydrogen bonding.