Crystal
structure prediction (CSP) has emerged as one of the most
important approaches for discovering new materials. CSP algorithms
based on evolutionary algorithms and particle swarm optimization have
discovered a great number of new materials. However, these algorithms
based on ab initio calculation of free energy are inefficient. Moreover,
they have severe limitations in terms of scalability. We recently
proposed a promising crystal structure prediction method based on
atomic contact maps, using global optimization algorithms to search
for the Wyckoff positions by maximizing the match between the contact
map of the predicted structure and the contact map of the true crystal
structure. However, our previous contact-map-based CSP algorithms
have two major limitations: (1) the loss of search capability due
to getting trapped in local optima; (2) it only uses the connection
of atoms in the unit cell to predict the crystal structure, ignoring
the chemical environment outside the unit cell, which may lead to
unreasonable coordination environments. Herein, we propose a novel
multiobjective genetic algorithm for contact-map-based crystal structure
prediction by optimizing three objectives, including contact map match
accuracy, individual age, and coordination number match. Furthermore,
we assign the age values to all the individuals of the GA and try
to minimize the age, aiming to avoid the premature convergence problem.
Our experimental results show that compared to our previous CMCrystal
algorithm, our multiobjective crystal structure prediction algorithm
(CMCrystalMOO) can reconstruct the crystal structure with higher quality
and alleviate the problem of premature convergence. The source code
is open sourced and can be accessed at .