  Recently Gilman has pointed out that the material state of a ball lightning
is both highly cohesive and flexible. He makes a specific proposal for a
cohesive state arising from (colossal) Van-der-Waals attraction between highly
polarizable Rydberg atoms produced under a linear lightning. We accept his
general suggestions but propose that the colossal Van-der-Waals coupling may
also arise from the enhanced polarizability of surrogate molecular clusters,
due to the polaron gap narrowing effect. We consider a few illuminating cases
and present calculations for the ammonia molecule. Although being unable to
identify the exact nature of the surrogate molecules at least for the
time-being, we suggest a general scenario of photoexcited vibronic excitons
forming a supersaturated surrogate gas phase in which a ball arises as a result
of condensation. The orange color of the luminous ball is due to radiative
exciton deexcitation and suggests that there may be a unique surrogate material
for ball lightning.
