**3. Results**

#### *3.1. Fitting Results*

In the fitting procedure, reference data were gathered from experimental results in the literature and FP calculations as supplements, especially for phases not observed in experiments. Fitted parameters are shown in Table 1. The functions defining the newly developed ADP are plotted in Figure 3.

**Figure 3.** Potential functions of the newly developed ADP. Embedding function *F*, electron density function *ρ* and pair potential *φ* are shown in (**a**–**c**), respectively; angular-dependent terms of *ψ*u, *ψ*<sup>v</sup> and *ψ*<sup>w</sup> are grouped together and plotted for elemental pairs of (**d**) U–U, (**e**) Mo–Mo and (**f**) U–Mo.

Fitting results of pure phases of U and Mo are shown in Tables 2 and 3. It could be seen that the lattice parameters were reproduced moderately well and the hierarchy of relative stability of allotropes was correctly reflected in terms of the cohesive energies. During fitting, specific attention was paid to the reproduction of elastic constants and the formation energies of defects. The fitting results of cross potentials of U–Mo are given in Table 4. During the fitting of the U–Mo cross potential, two configurations were

added to the database, since only the tetragonal phase of U2Mo has previously been found in experiments.


**Table 2.** Reproduced values of lattice constants, cohesive energies, and elastic constants of pure uranium.

**Table 3.** Reproduced values of lattice constants, cohesive energies, and elastic constants of pure molybdenum.


**Table 4.** Reproduced values of lattice constants, cohesive energies, and elastic constants of several U–Mo binary phases.

