Assignment of the photoelectron spectrum of HCl above 20 eV (original) (raw)

HCl+Xvibrational states investigated from the HCl threshold photoelectron spectrum

Physical Review A, 1991

The threshold photoelectron spectrum of HC1 has been investigated in the 980-760-A region. The various autoionization processes leading to the observed resonances are discussed. From the resonance positions 1ocated at the successive vibrational thresholds, spectroscopic constants of the X H state of HC1+ have been determined.

Photodissociation processes in the HCl molecule

Journal of Chemical Physics, 1982

Various ab initio methods have been employed for the study of photodissociation processes in the HCI molecule. Potential curves for selected singlet and triplet states and dipole transition moments between singlet states have been calculated. The transition moments vary significantly with internuclear distance for all states studied. The lifetime of the B 1,2' + state is predicted to be 3 ns. The calculations show that photodissociation of Hel occurs by absorption into the repulsive A III state and by absorption into the bound C III state, followed by predissociation. The theoretical photodissociation cross sections for the A III state and oscillator strengths for the C I II state are in good agreement with experimental data. The contributions from other excited states are investigated. The photodissociation rate of HCl in diffuse interstellar clouds is computed.

Ultraviolet photodissociation of HCl in selected rovibrational states: Experiment and theory

The Journal of Chemical Physics, 2000

Experimental and theoretical methods have been applied to investigate the effect of internal parent excitation on the ultraviolet photodissociation dynamics of HCl (X 1 ⌺ ϩ ) molecules. Jet-cooled H 35 Cl molecules within a time-of-flight mass spectrometer were prepared by infra-red absorption in the following quantum states: vϭ1, Jϭ0 and Jϭ5; vϭ2, Jϭ0 and Jϭ11; vϭ3, Jϭ0 and Jϭ7. The excited molecules were then photodissociated at ϳ235 nm and the Cl( 2 P j ) photofragments detected using ͑2ϩ1͒ resonance enhanced multiphoton ionization. The results are presented as the fraction of total chlorine yield formed in the spin-orbit excited state, Cl( 2 P 1/2 ). The experimental measurements are compared with the theoretical predictions from a time-dependent, quantum dynamical treatment of the photodissociation dynamics of HCl (vϭ1Ϫ3, Jϭ0͒. These calculations involved wavepacket propagation using the ab initio potential energy curves and coupling elements previously reported by Alexander, Pouilly, and Duhoo ͓J. Chem. Phys. 99, 1752 ͑1993͔͒. The experimental results and theoretical predictions share a common qualitative trend, although quantitative agreement occurs only for HCl (vϭ2).

Nonadiabatic effects in the photoelectron spectra of HCl and DCl.II. Theory

Physical Review A, 2002

The HCl inner-valence photoelectron band at 26 eV binding energy has been recorded at high resolution. Discrete peaks arising from at least two separate vibrational progressions are superimposed on the broad continuum. Fano profiles are visible in one of the progressions. This indicates interference between superimposed electronic states, where weak avoided crossing allows two adiabatic states to couple. In the isotopic DCl molecular spectrum, the discrete lines are less pronounced, due to slower dissociation and therefore less coupling between the continuum and the bound state.

Ultraviolet photodissociation of HCl in selected rovibrational states: Experiment …

The Journal of …

Experimental and theoretical methods have been applied to investigate the effect of internal parent excitation on the ultraviolet photodissociation dynamics of HCl (X 1 ⌺ ϩ ) molecules. Jet-cooled H 35 Cl molecules within a time-of-flight mass spectrometer were prepared by infra-red absorption in the following quantum states: vϭ1, Jϭ0 and Jϭ5; vϭ2, Jϭ0 and Jϭ11; vϭ3, Jϭ0 and Jϭ7. The excited molecules were then photodissociated at ϳ235 nm and the Cl( 2 P j ) photofragments detected using ͑2ϩ1͒ resonance enhanced multiphoton ionization. The results are presented as the fraction of total chlorine yield formed in the spin-orbit excited state, Cl( 2 P 1/2 ). The experimental measurements are compared with the theoretical predictions from a time-dependent, quantum dynamical treatment of the photodissociation dynamics of HCl (vϭ1Ϫ3, Jϭ0͒. These calculations involved wavepacket propagation using the ab initio potential energy curves and coupling elements previously reported by Alexander, Pouilly, and Duhoo ͓J. Chem. Phys. 99, 1752 ͑1993͔͒. The experimental results and theoretical predictions share a common qualitative trend, although quantitative agreement occurs only for HCl (vϭ2).

Nonadiabatic effects in photoelectron spectra of HCl and DCl. I. Experiment

Physical Review A, 2002

The HCl inner-valence photoelectron band at 26 eV binding energy has been recorded at high resolution. Discrete peaks arising from at least two separate vibrational progressions are superimposed on the broad continuum. Fano profiles are visible in one of the progressions. This indicates interference between superimposed electronic states, where weak avoided crossing allows two adiabatic states to couple. In the isotopic DCl molecular spectrum, the discrete lines are less pronounced, due to slower dissociation and therefore less coupling between the continuum and the bound state.

Photoabsorption, photodissociation, and photoionization cross sections of HCl

Physical Review A, 1990

Absolute absorption, ionization, and dissociation cross sections of HCl have been measured in the 980-720-A spectral range. Dipole moments have been obtained for several transitions. A quantum-defect-theory model with quantum-defect functions is used to describe the observed structures. The possible predissociation mechanisms are discussed. The dissociation excitation spectrum of DCl is assigned in the same way.

Neutral dissociation of hydrogen following photoexcitation of HCl at the chlorine K edge

Physical Review A, 1998

Time-of-flight mass spectroscopy was used to study the relaxation dynamics of HCl following photoexcitation in the vicinity of the Cl K edge (ϳ2.8 keV) using monochromatic synchrotron radiation. At the lowest resonant excitation to the 6* antibonding orbital, almost half of the excited molecules decay by emission of a neutral H atom, mostly in coincidence with a highly charged Cl nϩ ion. The present work demonstrates that neutral-atom emission can be a significant decay channel for excited states with very short lifetimes ͑1 fs͒.

High-Resolution Auger-Electron Spectrum of HCL and DCL

Physical Review A, 1989

The electron-impact excited high-resolution L2 3 VV Auger-electron spectra of HC1 and DC1 are presented. Four narrow bands are discerned that show a rich fine structure. Comparison between the HC1 and DC1 spectra shows this fine structure to be due to transitions to vibrational sublevels in the (2m) X, (2m.)'6, and (2~) 'X+ states of the doubly ionized molecule. By a Franck-Condon analysis the potential curves for all these doubly ionized states in the 2~configuration have been determined. The adiabatic double-ionization energies for the (2~) X, (2~)'6, and (2m)'X+ states were determined to be 35.68(5), 37.30(9), and 38.45(10) eV, respectively. The potential well is shallower than 1 eV for all these states, and dissociation occurs via a Coulombpotential mechanism. The double-ionization energies are used to assign a number of lines in the xray-excited photoelectron spectrum of HC1.