Low-Energy Electron Attachment to the Dichlorodifluoromethane (CCl2F2) Molecule

Results from a joint experimental study of electron attachment to dichlorodifluoromethane (CCl2F2) molecules in the gas phase are reported. In a high resolution electron beam experiment involving two versions of the laser photoelectron attachment method, the relative cross section for formation of the dominant anion Cl- wits measured over the energy range 0.001-1.8 eV at the gas temperature T-G = 300 K. It exhibits cusp structure at thresholds for vibrational excitation of the v(3)(a(1)) mode due to interaction with the attachment channels. With reference to the thermal attachment rate coefficient k(T-e;T-G = 300 K) = 2.2(8) x 10(-9) cm(-3) s(-1) (fitted average from several data), a new highly resolved absolute attachment cross section for TG = 300 K was determined. Partial cross sections for formation of the anions Cl-, Cl-2(-), F-, ClF-, and CCl2F- were measured over the range 0-12 eV, using three different electron beam experiments of medium energy resolution. The dependence of the attachment rate coefficient k(T-e;T-G = 300 K) on electron temperature T-e wits calculated over the range 50-15 000 K, based on a newly constructed total cross section for anion formation at T-G = 300 K. R-matrix Calculations for Cl- production have been carried out for comparison with the experimental data. The R-matrix results are in line with the main experimental observations and predict the dependence of the DEA cross section on the initial vibrational level v(3) and on the vibrational temperature. Furthermore, the cross section for I Vibrational excitation of the v(3) mode hits been computed.

Church of St George and St Thomas

Abstract: A vibrant inner city parish needed space for meetings, language classes, children’s play and other support accommodation as well as a clearer link between the interior of the listed church and the space outside.

The project builds itself about the entrance to the church. The form is manipulated such that the intervention recedes from those entering the church, drawing them into the plan before becoming readable as an addition. The resultant poché between this entrance sequence and the fabric of the church is hollowed out to provide the required accommodation. These rooms are insulated and lined in cork to allow for their use separate to the main body of the church. With budget at a premium the construction methodology was developed from an analysis of traditional Irish boat building techniques, which allowed the use of the solid timber to act as the primary structure with no additional material support.

Constructed in solid walnut the intervention reads with the existing brick interior and yet is clearly identifiable as a contemporary addition.

Aims / Objectives Questions

1 To accommodate new space inside an existing protected structure.
2 To form a new threshold between interior and exterior.
3 To develop an affordable means of construction that would be durable and rapid to erect.
4 To make a contemporary addition in sympathy with the qualities of the existing protect structure, in line with best conservation practice and research.
5 Traditional forms of construction as a model for contemporary technologies.