Vector Correlations in the 225 nm Photodissociation of Co(CO)NO.

Metal nitrosyls are fascinating compounds because they undergo significant geometry changes in the excited state. The volatile compound, Co(CO)NO, is a model for understanding the excited-state behavior. In this experiment, Co(CO)NO was photodissociated in a DC-sliced velocity mapping ion imaging apparatus with 1 + 1' resonance-enhanced multiphoton ionization (REMPI) detection of the nascent NO.

355 nm Photodissociation of NO Revealed by Velocity-Mapped Ion Imaging.

Dinitrogen trioxide is proposed as a precursor to forming nitrous acid, an important source of hydroxyl radicals in the atmosphere. The spectroscopy and properties of NO have been studied at high pressures or low temperatures, but there are no reports of its gas-phase photodissociation. This study investigates the 355 nm photodissociation of NO in a DC-sliced velocity-mapped ion imaging apparatus using linearly polarized nanosecond pump and probe lasers.

The photodissociation of N,N-dimethylnitrosamine at 355 nm: The effect of excited-state conformational changes on product vector correlations.

In a photodissociation experiment, the dynamics associated with creating reaction products with specific energies can be understood by a study of the product vector correlations. Upon excitation to the S state, N,N-dimethylnitrosamine (DMN) undergoes an excited-state geometry change from planar to pyramidal around the central N. The significant geometry change affects the vector correlations in the photoproducts.

A method for the determination of speed-dependent semi-classical vector correlations from sliced image anisotropies.

We present analytical expressions relating the bipolar moment β(Q)(K)(k(1)k(2)) parameters of Dixon to the measured anisotropy parameters of different pump/probe geometry sliced ion images. In the semi-classical limit, when there is no significant coherent contribution from multiple excited states to fragment angular momentum polarization, the anisotropy of the images alone is sufficient to extract the β(Q)(K)(k(1)k(2)) parameters with no need to reference relative image intensities. The analysis of sliced images is advantageous since the anisotropy can be directly obtained from the image at any radius without the need for 3D-deconvolution, which is not applicable for most pump/probe geometries.

UV photodissociation of η5-C5H5NiNO: an excited-state Jahn-Teller distortion produces a cartwheeling NO.

The 225 nm photodissociation of cyclopentadienylnickel nitrosyl was studied using velocity-mapped ion imaging with 1 + 1' REMPI detection of the NO (X (2)Π(1/2,3/2), v'' = 0) photofragment. The product recoil energy and angular distributions were measured for selected rotational states of NO. The NO product displays two speeds, a slow product peaked at the center of the ion image and a fast anisotropic product that has an inverted rotational population.

Determination of the v-j vector correlation in the photodissociation of nitrosobenzene at 305 nm.

The 305 nm photofragmentation dynamics of nitrosobenzene was measured using velocity-mapped ion imaging with polarized 1+1' resonance-enhanced multiphoton ionization probing of the NO (X, v"=0) fragment. The product recoil energy and angular distributions of selected rotational states of NO (X (2)Pi(1/2,3/2)) products have been measured. The recoil anisotropy of the NO photofragment is very small with beta(0)(2)(20)=0.