Investigation of the electronic structure of the TCNQ-TTF system: II. All-valence-electron band structures of infinite TCNQ and TTF chains

Abstract

We present in this paper energy band calculations for infinite chains of TCNQ, TCNQ 2−, TTI and TTI −2+ molecules by applying the CNDO/2 and, where possible, the MINDO/2 crystal orbital method. Different stacking distances were chosen. 1 or reasons of comparison we have also computed the corresponding TCNL chains. According to our findings poly (TCNQ) has a broad conduction band (≈0.6 eV) and a narrow valence band 1≈0.06 eV) while poly (TTl) has a broad valence band a narrow conduction band. The same holds true for the corresponding bands of poly (TCNQ 2-) and poly (TTl 2+). We give arguments that those findings apply also to the corresponding bands of the interesting case of poly (TCNQ −) and poly (TTI−+).