Full state-resolved energy gain profiles of CO2 from collisions with highly vibrationally excited molecules. II. Energy-dependent pyrazine (E = 32,700 and 37,900 cm(-1)) relaxation.

The full state-resolved distribution of scattered CO2 (00(0)0) molecules from collisions with highly vibrationally excited pyrazine (E = 32,700 cm(-1)) is reported and compared to previous studies on pyrazine (E = 37,900 cm(-1)) to investigate how internal energy content impacts the dynamics for collisional quenching of high energy molecules [J. Phys. Chem.

Pulsed ion extraction diagnostics in a quadrupole ion trap linear time-of-flight mass spectrometer.

Pulsed extraction techniques are investigated for a quadrupole ion trap (QIT) interfaced to a linear time-of-flight (TOF) mass analyzer. A nonfocusing short-pulse mode of operation is developed and characterized. The short-pulse mode creates a near-monoenergetic ion packet, which is useful for reaction kinetics experiments and for making diagnostic measurements of the ion cloud size in the trap.

Fluorescence and photodissociation of rhodamine 575 cations in a quadrupole ion trap.

The fluorescence and photodissociation of rhodamine 575 cations confined to a quadrupole ion trap are observed during laser irradiation at 488 nm. The kinetics of photodissociation is measured by time-dependent mass spectra and time-dependent fluorescence. The rhodamine ion signal and fluorescence decay are studied as functions of buffer gas pressure, laser fluence, and irradiation time.

Photodissociation and collisional cooling of rhodamine 575 cations in a quadrupole ion trap.

The photodissociation of rhodamine 575 cations held in a quadrupole ion trap is studied using 514 nm light as a function of buffer gas pressure, irradiation time, and laser fluence. The laser-induced photodissociation decays of rhodamine ions have lifetimes on the order of seconds for the range of pressures and powers investigated and exhibit strong nonlinear pressure dependence. Dissociation mechanisms are considered that involve the sequential absorption of multiple photons and several collisional deactivation steps.