State Of Sulfur Dioxide Research Articles

Ultrafast Photodissociation Dynamics of the F State of Sulfur Dioxide by Femtosecond Time-Resolved Pump-Probe Method

A femtosecond pump-probe method is employed to study the dissociation dynamics of sulfur dioxide. SO2 molecules are excited to the F state by absorbing two photons of 267 nm femtosecond laser pulses, and ionized by 400 nm laser pulses at different delay times between the two lasers. Transients of both parent ions (SO+2) and the fragment ions (SO+, S+ and O+) are observed. The SO+2 transient can be well fitted to a biexponential decay comprising a fast and a slow component of 280 fs and 2.97 ps lifetimes, respectively. The SO+ transient consists of two growth components of 270 fs and 2.50 ps. The results clearly show that the F state of SO2 dissociates along an S-O bond. The transients of S+ and O+, however, have different behavior, which consist of a fast growth and a long decay component. A possible mechanism of the fragment formation is discussed to understand the dissociation dynamics of the F state of SO2.

On the electronic excited states of sulfur dioxide

We report Ab Initio calculations for the ground and lowest electronic excited states of sulfur dioxide. Molecular geometries, together with the electric dipole moment, dipole polarizability and first hyperpolarizability are given for each state. Ground state properties were calculated using the HF and B3LYP models, whilst excited states were modelled using CIS and CIS(D). Our results reveal substantial differences between these properties.

SO 2: Origins of unequal bond lengths in the [formula omitted] electronic state

An experimentally established potential energy maximum and double minimum in the anti-symmetric stretching coordinate of the C ̃ state of sulfur dioxide is discussed. Comparison is made between (1) the usual assumption that the double minimum arises from promotion of an electron into an antibonding orbital, and (2) the possibility that the C ̃ 1B 2 state is vibronically coupled to higher lying 1 A 1 states. Two-state vibronic models are shown to reproduce the five observed levels of the ν 3 vibration of the C ̃ state.

Two-photon excitation of the [formula omitted] state of sulfur dioxide

The two-photon excitation (TPE) spectrum of sulfur dioxide is reported in the region of the C ̃ 1B 2 ← X ̃ 1A 1 [2b 1(π ∗) ← 1a 2(π)] transition. The spectrum shows considerable rovibronic structure; the band contours are identified as arising from Δ K −1 = ± 1 transitions and rotational features are assigned by comparison with synthetic spectra generated from known rotational constants. The vibronic structure observed in TPE is quite similar to that observed in the one-photon spectrum: no zero-rank tensor transitions to levels with odd v 3 are identified, though they are allowed in the presence of vibronic coupling. The vibronic intensity distribution in the TPE spectrum below the dissociation limit is similar to that in one-photon absorption. However, near the dissociation threshold (5.63–5.67 eV), marked intensity redistribution occurs, from which it is concluded that the lowest energy photo-dissociation process proceeds through asymmetric stretching of the SO bonds.

活性炭に対する排ガス中亜硫酸ガスの吸着状態

活性炭に対する排ガス中亜硫酸ガスの吸着状態