An optical spectrum, obtained by resonant two-photon ionization spectroscopy, is reported for jet-cooled diatomic gallium arsenide. The ground state is identified as X 3Σ−, deriving from a σ2π2 molecular configuration, and is characterized by ω″e=215 cm−1, ω″ex″e=3 cm−1, and r″0=2.53±0.02 Å. The upper state of the observed band system is 3Πr correlating to the Ga 4s24p, 2P0+As 4s24p3, 2D0 excited separated atom limit. A strong predissociation sets in above v′=0 for the Ω′=2,1 and 0− components of the 3Πr excited state, and it is proposed that this is induced by spin–orbit interaction with the σσ*π2, 5Σ− state which correlates to ground state atomic fragments. Constants for the upper 3Π0+ state are ω′e=152.13±0.70 cm−1, ωex′e=2.89±0.08 cm−1, and re=2.662±0.027 Å for the 69Ga75As isotopic modification. The ionization potential of GaAs has been bracketed as IP(GaAs)=7.17±0.75 eV, and a re-evaluation of the third-law measurement of the bond strength provides D0(GaAs)=2.06±0.05 eV. Comparisons to group IV and other group III-V diatomics, and to the bulk solid materials are also presented.

The dynamics of H2 dissociation on Cu and Ni surfaces. Mixed quantumclassical studies with all degrees of freedom J. Chem. Phys. 98, 5800 (1993); 10.1063/1.464873 Accurate threedimensional quantum scattering calculations for the F+H2 reaction on a new potential energy surface The bond dissociation energies of Tit, vt, Cot, and Cot have been measured from the sudden onset of predissociation in the photodissociation spectra of these molecules, yielding values of D o (Ti{)=2.435±0.002 eV, D o (Vt)==3.140±0.002 eV, Do(Cot) ==2.765 ±0.001 eV, and D o (Cot)=2.086±0.002 eV. These values are in good agreement with values previously determined from collision-induced dissociation experiments. General criteria for the interpretation of predissociation thresholds as bond dissociation energies and periodic trends in the bonding of the 3d transition metal diatomic neutrals and monocations are discussed.

New singlet Rydberg states of the NH(ND) radical in the energy range 92000-100000 cm−1 characterized by resonance enhanced multiphoton ionizationphotoelectron spectroscopy

No abstract

A new experimental apparatus has been constructed for photodissociation spectroscopy of transition metal-containing cations. redissociation thresholds for Co 2 + , Co 3 + , and Ti 2 + have been observed and values of 2.765 ± 0.001 eV, 2.086 ± 0.002 eV, and 2.435 ± 0.002 eV, respectively, have been determined for the bond energies for these species. These are in good agreement with results obtained by collision-induced dissociation (CID) experiments. Comparison of bond strengths obtained from the observation of predissociation thresholds with those obtained by non-optical methods, such as collision-induced dissociation and Knudsen cell mass spectrometry, have allowed criteria for the interpretation of a pre-dissociation threshold as a bond strength to be developed.