  Using the expansion on monomial functions of the Vandermonde determinant to
the power $\Gamma=Q^2/(k_BT)$, a way to find the excess energy $U_{exc}$ of the
two dimensional one component plasma 2dOCP on the hard and soft disk (or Dyson
Gas) for odd values of $\Gamma/2$ is provided. At $\Gamma=2$, the current study
not only corroborates the result for the particle-particle energy contribution
of the Dyson gas found by Shakirov by using an alternative approach but also
provides the exact $N$-finite expansion of the excess energy of the 2dOCP on
the hard disk. The excess energy is fitted to an ansatz of the form $U_{exc} =
K^1 N + K^2 \sqrt{N} + K^3 + K^4/N + O(1/N^2)$ to study the finite-size
corrections with $K^i$ coefficients and $N$ the number of particles. In
particular, the bulk term of the excess energy is in agreement with the well
known result of Jancovici for the hard disk in the thermodynamic limit.
Finally, an expression is found for the pair correlation function which still
keeps a link with the random matrix theory via the kernel in the Ginibre
Ensemble for odd values of $\Gamma/2$. A comparison between analytical 2-body
density function and histograms obtained with Monte Carlo simulations for small
systems and $\Gamma=2,6,10,\ldots$ shows that the approach described in this
work may be used to study analytically the crossover behaviour from a
disordered system to small crystals.
  Key words: Coulomb gas, one-component plasma, Ginibre ensemble, solvable
models
