Knowledge Bank

The first single photon threshlod ion-pair production spectrum (TIPPS) of a polyatomic molecule, $H2S$, was monitoring $H+$ ion generated from the dissociation process $H2S\to HS-+H+$. Its ion-pair threshold was determined to be $IPP=122458\pm 3cm-1$. As a result, the bond dissociation energy $(D(HS-H)=31451\pm 4cm-1)$ could be calculated from $D(HS-H)=IPP-IP(H)+EA(HS)$, by knowing the ionization potential of the hydrogen atom $(IP(H)=109678.772cm-1)$ and the electron affinity of the HS radical $(EA(HS)=18672\pm 2cm-1)$.