Matrix-block negative-factor-counting treatment of electron correlation in long alkane chains

Ab initio matrix-block negative-factor-counting calculations including electron correlation effects at the quasi-particle level have been performed on long linear alkane chains. Explicit results are given for C₃₆H₇₄, C₇₂H₁₄₆ and C₆₀₀H₁₂₀₂. It was found that the band edges in the photoelectron spectra for the CC and CH regions are already converged for these oligomers. On the other hand, band-shape formation inside the CH-regions is not yet complete for C₃₆H₇₄ from the theoretical point of view.