Effect of laser wavelength on the quantitative analysis performance of indirect ablation LIBS for analyzing the metals in lubricating oil.

For monitoring the lubricant quality and engine wear status, indirect ablation laser-induced breakdown spectroscopy (LIBS) was introduced to determine the metal elements in lubricating oil. Due to the different transmittance values of oil at different laser wavelengths, the effect of the laser wavelength on the detection performance of indirect ablation LIBS was studied. Under optimal parameters, the calibration curves were established for 10 metal elements with laser wavelengths of 1064, 532, and 355 nm.

Multiphoton Ionization/Dissociation of Molecular Sulfur S in the UV Region.

The multiphoton ionization/dissociation dynamics of molecular sulfur (S) in the ultraviolet range of 205-300 nm is studied using velocity map ion imaging (VMI). In this one-color experiment, molecular sulfur (S) is generated in a pulsed discharge and then photodissociated by UV radiation. At the three-photon level, superexcited states are accessed via two different resonant states: the Σ (' = 8-11) valence states at the one-photon level and a Rydberg state at the two-photon level.

Photoionization cross sections measurements of the excited states of lutetium and ytterbium in the near threshold region.

In this work, the threshold photoionization cross sections from the excited states of lutetium and ytterbium atoms were investigated by the laser pump-probe scheme under the condition of saturated resonant excitation. We obtained the resonance enhanced multiphoton ionization spectra of the lutetium and ytterbium atoms of the lanthanide metals in the range of 307.50-312.

Probing the Charge-Transfer Potential Energy Surfaces by the Photodissociation of [Ar-N].

Chemical reaction pathways and product state correlations of gas-phase ion-molecule reactions are governed by the involved potential energy surfaces (PESs). Here, we report the photodissociation dynamics of charge-transfer complex [Ar-N], which is the intermediate of the model system of the Ar + N → Ar + N reaction. High-resolution recoiling velocity images of photofragmented N and N from different dissociation channels exhibit a vibrational state-specific correlation, revealing the nonadiabatic charge-transfer mechanisms upon the photodissociation of [Ar-N].

Dissociation dynamics of carbon dioxide cation (CO ) in the CΣ state via [1+1] two-photon excitation.

The dissociation dynamics of CO in the CΣ state has been studied in the 8.14-8.68 eV region by [1+1] two-photon excitation via vibronically selected intermediate AΠ and BΣ states using a cryogenic ion trap velocity map imaging spectrometer.

N-loss photodissociation dynamics of NO(BΠ) near the NO(Σ+1) + N(P) dissociation limit.

Photodissociation dynamics of the NO cation in its BΠ state has been experimentally studied in an energy region around the NO(Σ) + N(P) dissociation limit using a cryogenic cylindrical ion trap velocity map imaging spectrometer. The results show that the NO(Σ) + N(D) product channel dominates the dissociation dynamics and requires the NNO angle to change by 30°-50° prior to dissociation. The NO(Σ) + N(P) product channel, which directly correlates with the BΠ state but less competitive, opens immediately when the photon energy reaches the dissociation limits, indicating a flat dissociation pathway without bending on the BΠ state surface.

AΠ and 1Σ States of Br Studied by [1+1] Two-Photon Dissociation Spectroscopy in a Cold Ion Beam.

The AΠ-XΠ and 1Σ-XΠ electronic transition spectra of Br have been studied in the 500-720 nm wavelength range in a cold ion beam using a cryogenic cylindrical ion trap velocity map imaging spectrometer. The cryogenic ion trap produces a rotationally and vibrationally cold mass selected ion beam of Br, which simplifies the experimental spectra from vibrational hot bands and bands of mixed isotopic species. Vibrationally resolved photofragment excitation spectra are recorded for individual isotopologues of Br (Br, BrBr, Br) by [1+1] two-photon dissociation spectroscopy.

A cryogenic cylindrical ion trap velocity map imaging spectrometer.

A cryogenic cylindrical ion trap velocity map imaging spectrometer has been developed to study photodissociation spectroscopy and dynamics of gaseous molecular ions and ionic complexes. A cylindrical ion trap made of oxygen-free copper is cryogenically cooled down to ∼7 K by using a closed cycle helium refrigerator and is coupled to a velocity map imaging (VMI) spectrometer. The cold trap is used to cool down the internal temperature of mass selected ions and to reduce the velocity spread of ions after extraction from the trap.

Photodissociation dynamics of OCS at ∼210 nm: The role of c(2A″) state.

Photodissociation dynamics of carbonyl sulfide (OCS) in the deep ultraviolet region is investigated using a time-sliced ion velocity map imaging technique. The measured total kinetic energy release spectra from the photodissociation of OCS at ∼210 nm shows three dissociation channels to the fragment S(D), corresponding to low, medium, and high kinetic energy release (E), respectively. The high E channel is found to be a new dissociation channel opening with photolysis wavelength at ∼210 nm.