S1 Supporting Information Conformational Complexity in the LH2 Antenna of the Purple Sulfur Bacterium Allochromatium vinosum Revealed by Hole- Burning Spectroscopy Adam Kell, 1 Mahboobe Jassas, 1 Khem Acharya, 1 Kirsty Hacking, 2 Richard J. Cogdell, 2 and Ryszard Jankowiak 1,3 1 Department of Chemistry and 3 Department of Physics, Kansas State University, Manhattan, KS 66506 United States 2 Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, Scotland Static Disorder The excitonic Hamiltonian is given by   =         +           with    () the excited state annihilation (creation) operator for pigment ,   is the pigment site energy and   is the coupling constant for pigments  and . Static disorder is introduced into the diagonal matrix elements (site energies) by Monte-Carlo disorder averaging and dichotomous conformation disorder. That is,   =   + Δ  + Δ  where    is the average site energy, Δ  is a normally distributed (with fwhm of Γ inh ) random energy shift and Δ  is the energy shift associated with conformations  = 1,2. Δ  = −Δ, =1 Δ, =2 As reported in the main text, Δ = 100 cm -1 for both B800 and B850 pigments. When performing the Monte-Carlo disorder averaging, the conformation of each pigment is assigned randomly from a uniform distribution with probability   (  +  =1). In previous studies, it is assumed that the thermally equilibrated transition rates between conformations follow the Boltzmann distribution with respect to the activation energy, leading to a temperature-dependent   determined by the activation energy. 1 The data reported in the main text of this work clearly reveals a significant population of conformation 2, suggesting that either the activation energy is