C. Crépin

Spectra and relaxation paths of Hg(3P1) in rare gas matrices

Absorption, fluorescence‐excitation and fluorescence spectra, and lifetimes have been measured for 3P1↔1S0 and 3P0→1S0 transitions in Hg atoms isolated in Ar, Kr, and Xe matrices. In all systems, the 3P1 state decays mainly by fluorescence emission; the 3P1■3P0 relaxation, inducing the long‐lived 3P0→1S0 emission, being very inefficient. The 3P1→1S0 emission in Ar and Kr is a mirror image of the absorption, while a strong redshift in Xe corresponds to the formation of Hg*Xe exciplexes. The results are discussed in a model assuming the additivity of interatomic potentials deduced from the spectroscopic studies of jet‐cooled Hg–rare‐gas complexes.

Infrared spectroscopy of aniline (C6H5NH2) and its cation in a cryogenic argon matrix

Infrared absorption spectra of aniline, trapped in a low-temperature 5 K argon matrix, have been obtained in the spectral region from 500 to 4000 cm−1. The aniline cation C6H7N+, was formed inside the matrix by UV laser irradiation. We report the first IR absorption spectroscopy of this cation in an argon matrix: five fundamental vibrational bands were observed.

Electronic spectra and proton transfer in the phenol/(NH3)n clusters in argon matrices

Abstract Absorption, fluorescence, phosphorescence and fluorescence- and phosphorescence-excitation spectra are recorded for the phenol/ammonia(Φ-OH/NH3) complexes, to Φ-OH..(NH3)2 and large Φ-OH..(NH3)n (n⩾3) clusters are identified. It is shown that the ionic form: Φ-O−..H in very large Φ-OH..(NH3)n clusters formed in pure ammonia and mixed NH3/Ar matrices with a high ammonia content. The results are compared to those obtained for free phenol-ammonia clusters formed in a supersonic expansion.

Ar+ laser-induced fluorescence spectra of Cs2: The E1Σu+ and (1) 1Πg electronic states

Abstract Laser-induced fluorescence of Cs2 molecules in the infrared (1.15–2.5 μm) and the visible (505–545 nm) regions has been observed using several excitation wavelengths from an argonion laser. Accurate molecular constants and potential energy curves for the pumped E1Σu+ state and the first excited gerade 1Π state are derived from more than 1300 fluorescence lines precisely measured with a high-resolution Fourier transform interferometer. The main molecular constants for the states are T e ( cm −1 ) ω e ( cm −1 ) B e ( cm −1 ) R e ( A ) E 1 Σ u + 20195.23 29.10 0.00891 5.340733 (1) 1 Π g 13913.42 18.44 0.00781 5.697722

A simulation of naphthalene matrix isolation : comparison with experiments

The trapping of a naphthalene molecule in an argon matrix is simulated using an original method based on classical molecular dynamics calculations. A numerical simulation of the gas mixture deposition on a cold argon surface reproduces the matrix growing process. Three main trapping sites are obtained. The naphthalene replaces four or five argon atoms in the (1 1 1) crystallographic plane, or four argon atoms in the (0 0 1) crystallographic plane of the fcc argon lattice structure. The simulated structures are correlated to experimental site effects: the spectroscopic and dynamic molecular properties depend only on the lattice plane occupied by the naphthalene.

Laser-induced fluorescence of CsH: The X1Σ+ state dissociation energy

Abstract Laser-induced fluorescence of CsH from the A 1 Σ + electronic state to the X 1 Σ + state was recorded using high-resolution Fourier transform spectrometry. Ground-state vibrational levels were observed from ν″ = 1 to the dissociation limit. These measurements showed anomalies in the X 1 Σ + potential energy curve due to the avoided crossing of ionic and covalent potential curves. Accurate molecular constants were derived for the lower X 1 Σ + vibrational levels. The observation of a quasibound level gave the first experimental determination of the dissociation energy (in cm −1 ): 14802 ⩽ D c ⩽ 14813.

Vibrational dynamics of CO stretching in W(CO)6-doped hybrid xerogels from 5 K to room temperature with the CLIO-FEL

One color pump-probe and photon-echo experiments have been performed on the CO stretching mode of W(CO) 6 at about 1982 cm -1 in organo-mineral xerogels. Over the whole temperature range studied, from room temperature to 5 K, the population lifetime T 1 remains constant when the vibrational dephasing time T 2 lengthens slightly. The temperature evolution of the pure dephasing time T * 2 reveals two activation energies corresponding to molecular motions of the guest in the xerogel pore.

The first two excited 1Σg+ states of Cs2

Abstract Laser-induced fluorescence Of Cs 2 molecules in the infrared region (4000–9000 cm −1 ) has been observed using several exciting wavelengths from an argon-ion laser and from a ring dye laser. Accurate molecular constants for the first two excited 1 Σ g + electronic states are derived from spectra recorded at high resolution by Fourier transform spectroscopy. Main molecular constants are: (2) 1 Σ g + : T c = 12114.090 cm −1 , ω e = 23.350 cm −1 , B c = 7.4.5 × 10 −3 cm −1 , R c = 5.8316 A; (3) 1 Σ g + : T e = 15975.450 cm −1 , ω e = 22.423 cm −1 , B e = 8.23 × 10 −3 cm −1 , R c = 5.5569 A.

Laser-induced infrared fluorescence of Cs2

Abstract Fluorescence induced by several exciting lines from an argon-ion laser has been recorded by high-resolution Fourier-transform spectrometry in the 4000-

The C3N− anion: First detection of its electronic luminescence in rare gas solids

The 193 nm laser irradiation of cyanoacetylene (HCCCN) that was isolated in rare gas solids led to a long-lived luminescence (origin at 3.58 eV), which was assigned to the a (3)Sigma(+)-X (1)Sigma(+) system of cyanoacetylide (CCCN(-)). The identification, which involved (15)N and (2)H isotopic substitution studies, is based on vibronic spacings in the phosphorescence spectrum (compared to previous infrared absorption measurements and to theoretical results regarding CCCN(-) vibrational frequencies), as well as on a BD(T)/cc-pVTZ prediction for the singlet-triplet energy gap in this anion (3.61 eV). The same emission was also generated from KrHC(3)N mixtures subjected to a glow electric discharge immediately before the solidification (cold-window-radial-discharge technique).