[1] Univ Oxford, Dept Phys, Clarendon Lab, Parks Rd, Oxford OX1 3PU, England
[2] Univ Oxford, Kavli Inst Nanosci Discovery, Dorothy Crowfoot Hodgkin Bldg, South Parks Rd, Oxford OX1 3QU, England
[3] Arizona State Univ, Sch Mol Sci, 1001 South McAllister Ave, Tempe, AZ 85281 USA
[4] Arizona State Univ, Biodesign Inst, Ctr Mol Design & Biomimet, 1001 South McAllister Ave, Tempe, AZ 85281 USA
[5] Tech Univ Munich, Sch Nat Sci, Dept Biosci, D-85748 Garching, Germany
[6] Univ Oxford, Dept Chem, Phys & Theoret Chem Lab, South Parks Rd, Oxford OX1 3QZ, England
[7] Univ Oxford, Rudolf Peierls Ctr Theoret Phys, 1 Keble Rd, Oxford OX1 3NP, England