def METHOD_NAME():
    """Dictionary of element ENDF data indexed by atomic symbol."""
    endf_data = os.environ['OPENMC_ENDF_DATA']
    elements = {'H': 1, 'O': 8, 'Al': 13, 'Cu': 29, 'Ag': 47, 'U': 92, 'Pu': 94}
    data = {}
    for symbol, Z in elements.items():
        p_file = 'photoat-{:03}_{}_000.endf'.format(Z, symbol)
        p_path = os.path.join(endf_data, 'photoat', p_file)
        a_file = 'atom-{:03}_{}_000.endf'.format(Z, symbol)
        a_path = os.path.join(endf_data, 'atomic_relax', a_file)
        data[symbol] = openmc.data.IncidentPhoton.from_endf(p_path, a_path)
    return data