def _RSquared_PSD_fitting_eqn(Omega, A, Gamma, Offset):
    """
    The value of the fitting equation:
    A / Gamma / (Omega**2 + Gamma**2)
    to be fit to the R Squared PSD signal, taken from equation 3 of paper
    (DOI: 10.1103/PhysRevResearch.2.023349) plus an additive offset.

    Parameters
    ----------
    Omega : float
        frequency in Radians
    A : float
        Multiplicative factor for the curve representing:
        8*(S_F/(2m^2*Omega0^2))^2
    Gamma : float
        Big Gamma (in Radians), i.e. damping
    Offset : float
        Additive Offset to the fitting equation.


    Returns
    -------
    Value : float
        The value of the fitting equation
    """
    return A / Gamma / (Omega**2 + Gamma**2) + Offset