Beschreibung:
<jats:title>Abstract</jats:title><jats:p>In reaction centers (<jats:styled-content style="fixed-case">RC</jats:styled-content>s) of photosynthesis, a light‐induced charge separation takes place creating radical cations and anions of the participating cofactors. In photosynthetic bacteria, different bacteriochlorophylls (<jats:styled-content style="fixed-case">BC</jats:styled-content>hl) are involved in this process. Information about the electronic structure of the <jats:styled-content style="fixed-case">BC</jats:styled-content>hl radical cations and anions can be obtained by measuring the electron spin density distribution <jats:italic>via</jats:italic> the electron–nuclear hyperfine interaction using <jats:styled-content style="fixed-case">EPR</jats:styled-content> and <jats:styled-content style="fixed-case">ENDOR</jats:styled-content> techniques. In this communication, we report isotropic hyperfine coupling constants (hfcs) of the <jats:styled-content style="fixed-case">BC</jats:styled-content>hl <jats:italic>b</jats:italic> and <jats:italic>g</jats:italic> radical cations and anions, calculated by density functional theory, and compare them with the more common radical ions of <jats:styled-content style="fixed-case">BC</jats:styled-content>hl <jats:italic>a</jats:italic> and with available experimental data. The observed differences in the computed hyperfine data are discussed in view of a possible distinction between these species by <jats:styled-content style="fixed-case">EPR</jats:styled-content>/<jats:styled-content style="fixed-case">ENDOR</jats:styled-content> methods. In addition, <jats:sup>14</jats:sup>N nuclear quadrupole coupling constants (nqcs) computed for <jats:styled-content style="fixed-case">BC</jats:styled-content>hl <jats:italic>a</jats:italic>,<jats:italic> b</jats:italic>,<jats:italic> g</jats:italic>, and also for Chl <jats:italic>a</jats:italic> in their charge neutral, radical cation and radical anion states are presented. These nqcs are compared with experimental values obtained by <jats:styled-content style="fixed-case">ESEEM</jats:styled-content> spectroscopy on several different radical ions.</jats:p>