The photodissociation of van der Waals molecules: Complexes of iodine, neon, and helium

Abstract

A supersonic free jet expansion was used to prepare van der Waals complexes of the type I2NeaHeb. Complexes containing as many as seven rare gas atoms were identified as satellites in the fluorescence excitation spectrum of the I2 B (v′=13 to 26) ←X (v″=0) band system by their relative dependence on the concentrations of neon and helium. For a+b?6, the frequencies of the van der Waals satellites follow a simple band shift rule: ν (I2NeaHeb) =ν (I2)+Aa+Bb, where A and B are weak functions of the I2 vibrational state. This observation, along with the failure of the rule for I2Ne7, provide some information concerning the geometry and binding in these molecules. Progressions (w′=0,1, and 2) in van der Waals modes of I2Ne and I2NeHe were also identified. The problem of intramolecular energy transfer was studied by observation of the dispersed emission spectra of the I2* fragments produced upon laser-induced photodissociation of these complexes. The product vibrational state distributions could be determined by using the known Franck–Condon factors and the observed intensities of the iodine transitions. All complexes required at least one I2 stretching quantum per rare gas atom for complete dissociation. Larger species favored dissociation channels involving more than one vibrational quantum per rare gas atom.

An empirical potential-energy surface for the He–I2(BΠu3) van der Waals complex including three-body effects

“…The experimental blueshifts are given in the last two columns with the reported errors. [23][24][25] In Fig. 2 the calculated and experimental blueshifts are plotted vs Ј.…”

Computational and experimental investigation of intermolecular states and forces in the benzene–helium van der Waals complex

“…[1][2][3][4][5][6] Interest in such species has continued into the present [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] for several reasons. First, the intermolecular forces pertaining to them are relatively simple.…”

Effect of Formation of van der Waals Complexes on Molecular Physical Properties

“…(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) and (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) we can see that the measurement of the spectral shift or ionization potential as a function of cluster size n in MAn can be used as a probe to study the molecular dynamics of clusters. [2][3][4][5][6][7] Investigations concerning the formation and properties of small clusters comprise an active area of research both experimentally and theoretically. To determine Ec(n)i--,a it is necessary to know gia(r), /a(/') and Ai(r).…”

“…Notice that for example (3)(4)(5)(6)(7)(8)(9) where ei(M) denotes the orbital energy for the i-th MO belonging to M. Next we consider the case of large n values; in this case except for a small number of adsorbed A's in the first several layers of MAn, the remaining adsorbed A's in MAn can be described by a distribution function gia(r). That is, E(n)i--,a--AEd(n)i--,a q-AE(n) (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17) where Ea(n)i-,a n[AE(a) Ai Here for simplicity it is assumed that besides n, na,.., the adsorbed A's are continuously distributed between ro and R. Notice that p in Eq. From Eqs.…”

“…For a given interaction potential function the radial distribution function can be determined not only for an extended system but also for small clusters. 3 The effect of the number of bound A's in MA. on the ionization potential due to the vdW complex formation can be treated similarly by using Eq.…”