  Defects in hexagonal boron nitride (hBN) exhibit single-photon emission (SPE)
and are thus attracting broad interest as platforms for quantum information and
spintronic applications. However, the atomic structure and the specific impact
of the local environment on the defect physical properties remain elusive. Here
we articulate X-ray photoelectron spectroscopy (XPS) and first-principles
calculations to discern the experimentally-observed point defects responsible
for the quantum emission observed in hBN. XPS measurements show a broad band,
which was deconvolved and then assigned to $N_{B}V_{N}$, $V_{N}$, $C_{B}$,
$C_{B}V_{N}$, and $O_{2B}V_{N}$ defect structures using Density Functional
Theory (DFT) core-level binding energy (BE) calculations.
