We carried out CCSD(T) geometry optimizations with the ATZ and AQZ basis sets, but to overcome the great computational cost of larger basis set calculations, we performed only a singlepoint quintuple-ζ basis set calculation at the geometry obtained with our quadruple-ζ basis set. We do not expect a significant structure variation from AQZ to A5Z basis sets, as the difference in bond length observed is less than 0.005 Å by improving from the ATZ to AQZ basis sets.