  Here we define a series of associative algebras attached to a vertex operator
algebra $V$, called mode transition algebras, showing they reflect both
algebraic properties of $V$ and geometric constructions on moduli of curves.
One can define sheaves of coinvariants on pointed coordinatized curves from
$V$-modules. We show that if the mode transition algebras admit multiplicative
identities with certain properties, these sheaves deform as wanted on families
of curves with nodes (so $V$ satisfies smoothing). Consequently, coherent
sheaves of coinvariants defined by vertex operator algebras that satisfy
smoothing form vector bundles. We also show that mode transition algebras give
information about higher level Zhu algebras and generalized Verma modules. As
an application, we completely describe higher level Zhu algebras of the
Heisenberg vertex algebra for all levels, proving a conjecture of
Addabbo--Barron.
