Kr Van Der Waals Research Articles

High resolution spectroscopic investigation of a new van der Waals complex: C2H2–Kr

The first observation in the near infrared of the (12)C(2)H(2)-Kr van der Waals complex is reported, leading to the determination of rotational constants and the prediction of the 1 0 1 (J'K(a)'K(c)') ← 0 0 0 (J''K(a)''K(c)'') microwave transition occurring at 3.334(4) MHz, useful for astrophysical detection.

High resolution infrared spectra of H2–Kr and D2–Kr van der Waals complexes

Infrared spectra of weakly bound hydrogen-krypton complexes have been studied at high spectral resolution (0.04 cm(-1)) using a long-path (154 m) low temperature (100 K) absorption cell and a Fourier transform spectrometer. In addition to spectra from the regions of the H(2) and D(2) fundamental vibrational bands in the midinfrared, the results also include the region of the pure rotational S(0)(0) transition of H(2) in the far infrared. A total of 219 measured line positions from these spectra have been fully assigned to specific quantum transitions and form the basis for determining a greatly improved semiempirical three-dimensional intermolecular potential energy surface for hydrogen-krypton in an accompanying paper.

Penning ionization electron spectroscopy of van der Waals clusters

Abstract A magnetic bottle electron spectrometer with retarding electrodes has been applied to observation of Penning ionization electron spectra (PIES) of van der Waals clusters. Considerably increased efficiency of the spectrometer by 1000 times over the conventional PIES apparatus enabled us to measure electron spectra of van der Waals clusters of rare gas atoms in collisions with metastable atoms, He*(2 3 S) and Ne*(3 3 P). Unusually fast electrons with extra kinetic energies of 1–2 eV as compared to those expected for vertical ionization have been detected for Ar and Kr van der Waals clusters in collisions with He*(2 3 S). These fast electrons are ascribed to autoionization into stable ionic structures via superexcited states embedded in the ionization continua, and the unusual electrons can be considered to be related to an adiabatically ionized state to which a direct ionization process is almost forbidden because of a very small Franck–Condon factor.

(2+1) REMPI spectra of the I2–Krand I2–N2van der Waals complexes and the (2+1[prime ]) ZEKE[ndash ]PFI photoelectron spectrum of I2+–Kr

We present the (2 + 1) mass-resolved resonance-enhanced multiphoton ionisation (REMPI) spectrum of the [2Π3/2]c5d;Ωg (Ω = 0,2) Rydberg states of the I2–Kr van der Waals complex. Anharmonic progressions in the I2···Kr van der Waals stretching mode have been observed with e values of 49 ± 2 and 47 ± 2 cm−1 for the [2Π3/2]c5d;Ω = 0g and [2Π3/2]c5d;Ω = 2g states, respectively. The [2Π3/2]c5d;Ω = 2g state of I2–Kr has been used as an intermediate in a two-colour (2 + 1′) zero kinetic energy pulsed-field ionisation (ZEKE–PFI) photoelectron study of the 2Π3/2,g state of the I2+–Kr ionic complex. The adiabatic ionisation energy was determined to be 74248 ± 3 cm−1. An anharmonic vibrational progression in the I2+···Kr van der Waals stretching mode was observed giving a value of e = 55 ± 2 cm−1 for the 2Π3/2,g state of the complex. The [2Π1/2]c6s;Ω = 1g Rydberg state of the I2–N2 van der Waals complex has also been observed using REMPI spectroscopy. Anharmonic progressions in the I2···N2 van der Waals stretching mode have been observed with e = 71 ± 2 cm−1. Comparisons are made between the spectroscopic data obtained for the Rydberg states of I2–Kr and I2–N2 with the analogous Rydberg states in I2–Ar.

Infrared dissociation spectroscopy of the OH stretching vibration of phenol—rare gas van der Waals cluster ions

Infrared dissociation spectra of phenol—Ar and —Kr van der Waals cluster ions in supersonic free jets were observed in the absorption region of the OH stretching vibration. Both spectra showed the OH stretching vibration at 3535 ± 2 cm −1, indicating that the perturbation of the rare gases is small and the observed frequency represents that of the bare phenol ion. The vibrational frequency of the phenol ion was found to be 122 cm − smaller than that of neutral phenol.

Alignment effects in the photodissociation of Hg–Kr van der Waals molecules

In this paper we present calculations of the yield and polarization of the fluorescence from the Hg λ253.7 nm transition following photodissociation of the Hg–Kr van der Waals molecule. We have used a coupled channel wave packet method to predict the alignment produced in photodissociation [J. Chem. Phys. 95, 8124 (1991)]. We show that the alignment effects depend sensitively on the repulsive part of potential near photodissociation threshold. We have made predictions for three different sets of interatomic potentials for Hg–Kr proposed by different authors [M. Findeisen and T. Grycuk, J. Phys. B 22, 1583 (1988); M. Findeisen, T. Grycuk, and J. Staby, The B and X State Potentials for Hg–Ar, –Kr, –Xe (to be published); M. Okunishi, H. Nakazawa, K. Yamanouchi, and S. Tsuchiya, J. Chem. Phys. 93, 7526 (1990); D. M. Segal and K. Burnett, J. Chem. Soc. Faraday Trans. 2 85, 925 (1989)].

Some remarks on the interpretation of satellites of the mercury 2537 Å line in the presence of noble gases

New measurements of satellites of the mercury 2537 Å line in the presence of krypton are reported. A high resolution spectrophotometer with a double-channel detecting system was used. The results obtained show that the structure appearing in the wings of the perturbed line arises from two effects: pressure induced satellite bands of HgKr van der Waals complexes and vibrational spectrum of the Hg 2 dimer. The contribution of the latter is demonstrated experimentally by a careful study of the spectrum of pure mercury vapour. It has been shown that this effect is responsible for the series of sharp red bands observed previously in fluorescence by some authors and interpreted there as a result of transitions between bond and free vibrational states in Hgnoble gas systems.