Electron affinity and substituent effects in radical anions

The first vertical electron affinities EA of 13 series of molecules and free radicals D(Xi)n are related to the inductive (σI), resonance (σR−), and polarization (σα) parameters of substituents Xi by the dependences EA = EAH + aΣσI + bΣσR/− + cΣσα: In radical anions D+·(Xi)n, compared to radical cations D+·(Xi)n, the polarization interaction is weaker or similar in magnitude but has an opposite sign. The previously unknown resonance parameters σR− of substituents SiMe3 and CH2SiMe3 bound to the radical anion center H2C=CH−· were calculated.