The estimation of the second virial coefficients of He and N2 based on neural network potentials with quantum mechanical calculations

Abstract

• We test the accuracy of the neural network potentials against the virial coefficient of He and N2. • The second virial coefficients from the neural network potential is quite accurate for He at T > 200 K. • This study indicates that the level of quantum chemical calculation still play an important role. We test the accuracy of the neural network interaction potentials against accurate thermodynamic data of He and N 2 . We perform single point energy calculations at CCSD(T) level, construct the intermolecular interactions by using neural networks, and perform Monte Carlo simulations to calculate virial coefficients. We find that the deviation of virial coefficients from previous studies is small for He while the difference is about 3 cm 3 mol −1 for N 2 . Our results show that when trying to obtain accurate thermodynamic data from the neural network interaction potentials, not only the level of quantum chemical calculations should be an important factor, but also at least thousands of training data points would be required.