Implications on the Band Structure of the Isostructural Family Tetrathiafulvalene Tetracyanoquinodimethane (TTF-TCNQ), Tetraselenafulvalene Tetracyanoquinodimethane (TSeF-TCNQ), and Their Solid Solutions from Spin-Resonance Measurements

We show that electron-phonon coupling plays a major role in the spin relaxation of the isostructural family of organic metals, ${\left(\mathrm{TSeF}\right)}_x{\left(\mathrm{TTF}\right)}_{1-x}\mathrm{TCNQ}$ (tetraselenafulvalene tetrathiafulvalene tetracyanoquinodimethane). The dependence of this relaxation on the fraction of TSeF in the donor chain suggests a picture of hybridized donor-acceptor bands for TSeF-TCNQ in contrast to the nonhybridized bands of TTF-TCNQ.