# Method for the calculation of the Hamaker constants of organic materials by the Lifshitz macroscopic approach with DFT

## TL;DR

This paper presents a method to calculate Hamaker constants for organic materials using Lifshitz theory combined with DFT calculations, avoiding experimental measurements and enabling quick molecular modeling.

## Contribution

The study introduces a DFT-based approach to compute Hamaker constants for various organic materials using Lifshitz theory, simplifying and speeding up the process.

## Key findings

- Calculated Hamaker constants closely match experimental values for non-associative materials.
- The method reduces computational time and simplifies molecular modeling.
- Applicable to a wide range of organic compounds.

## Abstract

The Hamaker constants, which are coefficients providing quantitative information on intermolecular forces, were calculated for a number of different materials according to the Lifshitz theory via simple DFT calculations without any experimental measurements being performed. The physical properties (polarizability, dipole moment, molecular volume, and vibrational frequency) of organic molecules were calculated using the B3LYP density functional and the aug-cc-pVDZ basis set. Values for the Hamaker constants were obtained using the approximation of the Lorentz-Lorenz equation and Onsager's equation with these properties. It was found that, in the case of `non-associative' materials, like hydrocarbons, ethers, ketones, aldehydes, carboxylic acids, esters, nitriles, and hydrosilanes, and halides, the calculated Hamaker constants were similar in value to their experimentally determined counterparts. Moreover, with this calculation method, it is easy to create the molecular model and the CPU time can be shortened.