def fit_radius_from_potentials(z, SampleFreq, Damping, HistBins=100, show_fig=False):
    """
    Fits the dynamical potential to the Steady 
    State Potential by varying the Radius.
    
    z : ndarray
        Position data
    SampleFreq : float
        frequency at which the position data was 
        sampled
    Damping : float
        value of damping (in radians/second)
    HistBins : int
        number of values at which to evaluate 
        the steady state potential / perform
        the fitting to the dynamical potential

    Returns
    -------
    Radius : float
        Radius of the nanoparticle
    RadiusError : float
        One Standard Deviation Error in the Radius from the Fit
        (doesn't take into account possible error in damping)
    fig : matplotlib.figure.Figure object
        figure showing fitted dynamical potential and stationary potential
    ax : matplotlib.axes.Axes object
        axes for above figure

    """
    dt = 1/SampleFreq
    boltzmann=Boltzmann
    temp=300 # why halved??
    density=1800
    SteadyStatePotnl = list(steady_state_potential(z, HistBins=HistBins))
    yoffset=min(SteadyStatePotnl[1])
    SteadyStatePotnl[1] -= yoffset

    SpringPotnlFunc = dynamical_potential(z, dt)
    SpringPotnl = SpringPotnlFunc(z)
    kBT_Gamma = temp*boltzmann*1/Damping
    
    DynamicPotentialFunc = make_dynamical_potential_func(kBT_Gamma, density, SpringPotnlFunc)
    FitSoln = _curve_fit(DynamicPotentialFunc, SteadyStatePotnl[0], SteadyStatePotnl[1], p0 = 50)
    print(FitSoln)
    popt, pcov = FitSoln
    perr = _np.sqrt(_np.diag(pcov))
    Radius, RadiusError = popt[0], perr[0]

    mass=((4/3)*pi*((Radius*10**-9)**3))*density
    yfit=(kBT_Gamma/mass)
    Y = yfit*SpringPotnl
    
    fig, ax = _plt.subplots()
    ax.plot(SteadyStatePotnl[0], SteadyStatePotnl[1], 'bo', label="Steady State Potential")
    _plt.plot(z,Y, 'r-', label="Dynamical Potential")
    ax.legend(loc='best')
    ax.set_ylabel('U ($k_{B} T $ Joules)')
    ax.set_xlabel('Distance (mV)')
    _plt.tight_layout()
    if show_fig == True:
        _plt.show()
    return Radius*1e-9, RadiusError*1e-9, fig, ax