Knowledge Bank

Multiple features associated with transitions of the near T-shaped and linear $Ne\cdots I35,37Cl(X,\nu \prime \prime =0)$ isomers are observed in laser-induced fluorescence spectra recorded in the $IClB-X$, $2-0$ and $3-0$ spectral regions. The T-shaped complexes access the lowest intermolecular vibrational level within the $Ne+ICl(B,\nu \prime )$ potential, while the linear complexes access at least four different bending levels that are delocalized in the angular coordinate. The ground state binding energy of the linear $Ne\cdots I35Cl$ isomer is directly measured in two-laser, action spectroscopy experiments. A continuum signal is observed with a turn on at $17748.4cm-1$ that indicates a binding energy of $84.3(2.3)cm-1$ for the ground state complex. The ground state binding energy of the T-shaped isomer can be estimated by fitting the $Ne\cdots I35Cl(B,\nu \prime =2)$ bending levels that the ground state linear isomer accesses to an $\omega e,\omega e\chi e$ progression. The fit reveals a binding energy of $60.8(3.2)cm-1$ for $Ne\cdots I35Cl(B,\nu \prime =2)$, which implies a T-shaped ground state binding energy of $66.2(3.2)cm-1$ based upon the spectroscopic shift of the T-shaped feature from the $I35ClB-X,2-0$ transition. Two-laser, pump-probe experiments were also performed to access the intermolecular vibrational levels that are bound within the $Ne+ICl(E0+,\nu =10)$ ion-pair state. In these experiments, the pump laser was fixed on either the lowest energy level, with a T-shaped equilibrium geometry, or one of the higher energy delocalized levels within the $Ne+I35Cl(B,\nu \prime =2)$ well. In this manner, varying $Ne\cdots I35Cl$ Franck-Condon windows between the B and E states are accessed and assignments of the intermolecular vibrational levels within the ion-pair state can be made. The results suggest a $Ne+ICl(E0+)$ potential with the lowest bound level localized in the T-shaped orientation and that the higher energy levels are delocalized in the angular coordinate.