1. Unilever Research and Development, Port Sunlight Laboratory, Quarry Road East, Bebington, Wirral CH63 3JW, U.K.
2. ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, OXON, U.K.
3. Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, U.K.