  We have analyzed spectral weight changes in the conduction and the valence
band across insulator to metal transition (IMT) in the VO2 thin film using
X-ray absorption spectroscopy (XAS) and resonant photoemission spectroscopy
(PES). Through temperature dependent XAS and resonant PES measurements we
unveil that spectral changes in the d$_{\|}$ states (V 3$\it{d_{x^2-y^2}}$
orbitals) are directly associated with temperature dependent electrical
conductivity. Due to presence of the strong electron-electron correlations
among the d$_{\|}$ states, across IMT, these states are found to exhibit
significant intensity variation compared to insignificant changes in the
$\pi^{\ast}$ and the $\sigma^{\ast}$ states (which are O 2$\it{p}$ hybridized V
3$\it{d}$ $e_g^{\pi}$ and $e_g^{\sigma}$ states) in the conduction band.
Experimentally obtained values of the correlation parameter (U$_{dd}$ $\sim$
5.1 eV, intra-atomic V 3$\it{d}$ correlations) and crystal field splitting (10
Dq $\sim$ 2.5 eV) values are used to simulate the V $\it{L_{2,3}}$ edge XAS
spectra and an agreement between simulated and experimental spectra also
manifests strong correlations. These results unravel that the IMT observed in
the VO2 thin film is the Mott-Hubbard insulator-metal transition.
