- Merrill et al. have said that “while solutions to the [HF equations] may be
viewed as exact solutions to an approximate description, the [KS equations] are
approximations to an exact description!” Explain. - Electronegativity is the ability of an atom or molecule to attract electrons. Why
then is it (from one definition) the average of the ionization energy and the
electron affinity (Eq.7.32), rather than simply the electron affinity? - Given the wavefunction of a molecule, it is possible to calculate the electron
density function. Is it possible in principle to go in the other direction? Why or
why not? - The multielectron wavefunctionCis a function of the spatial and spin coordi-
nates of all the electrons. Physicists say thatCfor any system tells us all that
can be known about the system. Do you think the electron density functionr
tells us everything that can be known about a system? Why or why not? - If the electron density function concept is mathematically and conceptually
simpler than the wavefunction concept, why did DFT come later than wave-
function theory? - Is a metal, with its common pool of electrons, a good approximation of the
homogeneous electron gas of early DFT theory? Why or why not?
Harder Questions 519