Rydberg states of the ArCO₂ and KrCO₂ van der Waals molecules

Journal Article · Tue Jan 01 04:00:00 EST 1985 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.449817· OSTI ID:5646372

Dehmer, Patricia M. ^[1]

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1. Argonne National Lab. (ANL), Argonne, IL (United States)

Relative photoionization cross sections were determined for ArCO₂ at a wavelength resolution of 0.24 A in the regions of both the Ar*+CO₂ and the Ar+CO₂* dissociation limits (690--920 Â) and for KrCO₂ at a wavelength resolution of 0.4 Â in the region of the Kr+CO₂* dissociation limits (690--780 Â). The dimer ionization potentials are 13.59±0.04 eV (912.5±2.5 Â) for ArCO₂ and 13.33±0.04 eV (930.0±3.0 Â) for KrCO₂. Combining these values with the known value of the CO₂ ionization potential and the known (or estimated) values of the ArCO₂ and KrCO₂ dissociation energies yields values for the dimer ion ground state dissociation energies of 0.20±0.04 eV for ArCO₂⁺ and 0.47±0.05 eV for KrCO₂⁺. Rydberg structure is observed in the photoionization cross section of ArCO₂ corresponding to dissociation limits of the type Ar*(nd,ns)+CO₂; however, discrete structure is observed only near the Ar*(3d,5s)+CO₂ dissociation limits. Van der Waals structure corresponding to the higher Ar*+CO₂ limits is diffuse and red degraded. Molecular Rydberg structure also is observed in the photoionization cross sections of both ArCO₂ and KrCO₂ corresponding to dissociation limits of the type Ar+CO₂*. Prominent van der Waals structure is observed corresponding to dissociation limits based on members of the CO₂ Henning sharp and diffuse Rydberg series, which converge to CO₂⁺ B ²Σ_u⁺ ; however, no van der Waals structure is observed corresponding to dissociation limits based on members of the CO₂ Tanaka–Ogawa Rydberg series, which converge to CO₂⁺ A ²Π_u . Various experimental evidence indicates that neither vibrational predissociation of the excited van der Waals dimer nor vibrational predissociation of the dimer ion can account completely for the absence of van der Waals structure corresponding to the Tanaka–Ogawa series in CO₂.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE; Office of Naval Research (ONR)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5646372
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 1 Vol. 83; ISSN JCPSA6; ISSN 0021-9606
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ADDUCTS
ARGON
ARGON COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CROSS SECTIONS
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
GASES
IONIZATION
KRYPTON
KRYPTON COMPOUNDS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHOTOIONIZATION
RARE GAS COMPOUNDS
RARE GASES
RYDBERG STATES
VAN DER WAALS FORCES