Table 2. Simulation parameters for virtual NR measurements of the solid-supported lipid bilayer shown in Fig. 3 ▸(a), in which the isotopic composition of the bilayer and one bulk solvent nSLD were systematically varied.
Where ranges are given in the first data column, the parameter was systematically varied within these boundaries during the optimization. The nSLD of bulk Si is fixed at 
= 2.07 × 10−6 Å−2. If the bilayer was characterized using more than one solvent, each additional measurement carried its own parameter for the solvent nSLD and the scattering background.
| Model parameter | Parameterized sample representation, 
|
Fit boundaries, prior PDF limits |
|---|---|---|
| Thickness of Si oxide (Å) | 18 | [10, 30] |
| nSLD of Si oxide (10−6 Å−2) | 3.55 | [3.2, 3.8] |
| Thickness of sub-membrane water layer (Å) | 2.5 | [1, 10] |
| Thickness of hydrocarbon chains per bilayer leaflet (Å) | 14.1 | [10, 20] |
| Molar fraction of DPPC-d62 in the membrane | [0.0, 1.0] | [0.0, 1.0] |
| Volume fraction of lipid bilayer | 0.95 | [0.9, 1.0] |
| nSLD of bulk solvent (10−6 Å−2) | [−0.5, 6.5] | ±0.5 |
Interfacial roughness,  (Å) |
3 | ±2 |
| Bilayer roughness, (Å) |
2.5 | [2, 5] |
| Log10 of background | −8 | ±1 |