1. Department of Chemistry, University of Warwick, Gibbet Hill, Coventry CV4 7AL, U.K.
2. Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K.
3. School of Physical Sciences, University of Kent, Canterbury CT2 7NH, U.K.
4. Diamond Light Source, Harwell Campus, Didcot, Oxfordshire OX11 0DE, U.K.