The modified embedded-atom method, a first nearest-neighbor semiempirical model for atomic potentials, can describe the physical properties of a wide range of elements and alloys with various lattice structures. However, the model is not quite successful for bcc metals in that it predicts the order among the size of low index surface energies incorrectly and that it generates a structure more stable than bcc for some bcc metals. In order to remove the problems, the formalism has been extended so that the second nearest neighbor interactions are taken into consideration. New parameters for Fe and comparisons between calculated and experimental physical properties of Fe are presented.Semiempirical atomic potentials enable atomistic simulation ͑molecular dynamics or Monte Carlo simulation͒ with a large number of atoms, which can be a powerful technique to study solid state phase transformations. In order to apply the technique to alloys, it is essential to describe the atomic potentials of various elements with various crystal structures using the same formalism. The modified embedded-atommethod ͑MEAM͒ potential proposed by Baskes et al. 1-4 may be said to be unique in that it can reproduce physical properties of many metals with various crystal structures including hcp and diamond cubic as well as fcc and bcc using the same formalism.However, when being applied to an atomistic simulation on some bcc metals, the MEAM reveals that it has critical problems to be solved. First, for many bcc metals, the surface energy of ͑111͒ surface is computed to be smaller than that of the ͑100͒ surface, which is contrary to experimental information. 5,6 Second, a structure more stable than the bcc is created during a molecular dynamics simulation on some bcc metals ͑Fe,Cr,Mo, . . . ͒. The metals with the newly created structure have quite different elastic properties compared to the metals with the original structure. Simply changing the model parameters cannot solve these problems, without losing good descriptions for other physical properties.The MEAM was formulated to consider only nearestneighbor interactions by using a strong screening function. 3,7,8 However, in the bcc structure, the second nearest-neighbor distance is larger than the first nearestneighbor distance only by about 15%. The interactions between second nearest-neighbor atoms may not be negligible in this structure even with the screening. It is possible that the failure of the MEAM in reproducing the surface energies of low index surfaces in the correct order originates from the fact that only the nearest-neighbor interactions are considered in the model.The purpose of the present work is to show that the above mentioned problems of the MEAM for bcc metals can be removed by modifying the MEAM formalism so that it considers partially the second nearest-neighbor interactions as well as the first nearest-neighbor interactions. The new formalism, the parameters of Fe according to the new formalism and comparisons between some computed and experimental physical prope...

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We discuss the dominant factors influencing the rate of oxidation of Ti3C2TxMXene flakes, and present guidelines for their storage with the aim of maintaining the intrinsic properties of the as-prepared material.