Experimental and Theoretical Studies of the HeICl Van der Waals Complexes in the Valence and Ion-pair States.

The article presents results of experimental and theoretical analysis of the T-shaped and linear HeICl van der Waals complexes in the valence A1 and ion-pair ß1 states as well as the HeICl(A1,vA ,nA ←X0+ ,vX =0,nx and ß1,vß ,nß â†A1,vA ,nA ) optical transitions (ni are quantum numbers of the vdW) modes). The HeICl(ß1,vß ,nß )→He+ICl(E0+ , D ' 2 ${{D}^{{ {\prime}}}2}$ , ß1) decay are also studied. Luminescence spectra of the HeICl(ß1,vß =0-3,nß ) complex electronic (ICl(E0+ ,vE , D ' 2 , v D ' ${{D}^{{ {\prime}}}2,{v}_{{D}^{{ {\prime}}}}}$ ) and vibrational ICl(ß1,vß ) predissociation products are measured, and branching ratios of decay channels are determined. To construct potential energy surfaces for the HeICl(A1, ß1) states, we utilized the intermolecular diatomic-in-molecule perturbation theory first order method. Experimental and calculated spectroscopic characteristics of the A1 and ß1 states agree well. Comparison of the experimental and calculated pump-probe, action and excitation spectra shows that the calculated spectra describe the experimental spectra adequately.

Experimental and theoretical investigation of the ArICl van der Waals complexes in the valence and ion-pair states.

This paper presents the experimental and theoretical analyses of ArICl(IP,vIP,nIP) states' population and decay at energies lower than the ArICl(E,vE = 0,nE) dissociation limit (IP = E0+, D'2, ß1), vIP = 0, 1, and nIP are the quantum numbers of the van der Waals (vdW) modes. We have measured the excitation spectra of the ArICl(E,vE = 0,1,nE → X,vX,nX) and ArICl(ß,0,nß â†’ A and/or D',vD' ,nD' →A' luminescence as well as luminescence spectra themselves. To construct potential energy surfaces (PESs) for valence (A1, A'2) and ion-pair (E, ß, and D') electronic states of the complex, we utilized the intermolecular diatomic-in-molecule perturbation theory first order method. The experimental and calculated spectroscopic characteristics of the T-shaped ArICl valence and E, ß states agree well. The ArICl(D') state PES has no vdW levels in the T-shaped configuration, and collinear ArICl(D') binding energy is larger than that of the T-shaped ArICl(ß) state. We calculated vibrational state energies and the ArICl(IP → valence states) luminescence excitation spectra, as well as luminescence spectra themselves, by using the Heidelberg MCTDH code. The comparison of the experimental and calculated excitation spectra shows that the latter describe their principal features. The bound-bound ArICl(E,0,nE → X and ß,0,nß â†’ A) parts of experimental luminescence spectra are described adequately by the calculated spectra, whereas bound-free ArICl(E,0,nE → X, D', 0, nD' → A') parts are not described since the bound-free transitions occur in repulsive parts of the ArICl(X, A' PESs, which we cannot describe accurately.