Imagine a sample of solid metal at room temperature. It exhibits resistance to compression which is expressed as its bulk modulus. Part of this resistance originates from a treatment of the delocalized valence electrons as an electron gas which resists compression because of degeneracy pressure and part of it is due simply to electrostatic forces between adjacent atoms and that electron gas. Here are my questions:
At room temperature, what are the relative contributions of these two different mechanisms to the bulk modulus we measure in the lab? and
If we exert negative (i.e., tensile) pressure on that same sample, one would think that the degeneracy pressure contribution would lessen since we are no longer trying to force electrons into the same quantum energy level- which would leave the electrostatic mechanism the dominant one for metals in tension. Is this true- that is, do we measure different values for the bulk modulus in triaxial compression versus expansion?
