The Vibrational Stiffness of an Atomic Lattice
Abstract
A static atomic model is described, which may be employed to evaluate the characteristic vibrational stiffness of an atomic lattice, given the pairwise potential of the constituent atom. Because the vibrational stiffness is directly related to the resultant vibrational frequency spectrum of the lattice, the method may be used to infer the behavior of the characteristic lattice frequency as a function of lattice spacing. The characteristic frequency behavior is sufficient to determine the Grueneisen function, an important thermodynamic parameter relating to thermal behavior of a crystal lattice. The current method computes and utilizes several spring constants derived from a static lattice in order to infer the characteristic vibrational behavior. No atomic dynamics calculations involving either the equations of motion or modal (vibrational) analysis are required. As such, the method generally requires mere seconds of computation on today's generation of desktop workstations. Results indicate that the vibrational stiffness of the lattice is qualitatively distinct from the volumetric stiffness of the lattice, and, furthermore, that the resulting lattice behavior can be described, over a wide region of lattice spacing, by an analytical equation of state in terms of lattice frequency.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1998
- Accession Number
- ADA353163
Entities
People
- Steven B. Segletes
Organizations
- United States Army Research Laboratory