The crossover of phase transitions from NaCaF3 to KCaF3

We have performed molecular dynamics simulations on a series of 320 ion samples of NaCaF3 with specific amounts of randomly distributed K substituted for Na. Our computations used ab initio potentials with no adjustable parameters to calculate the short range interactions between ion pairs in these samples. Our results indicate the gradual crossover of the phase transitions from NaCaF3 to KCaF3. The polar state seems to disappear at a K to Na ratio of three.