Table 1. Correlation times, extrapolated R_v(0), dipolar area ratios, and θ_PH angles for a variety of phospholipid vesicles.

Sample*	τv, μs	Rv(0), s-1	Area ratio†	θPH(+)‡	θPH(-)‡
POPC/DOPMe
POPC	0.54 ± 0.10	8.4 ± 2.3	0.080	43.7	67.7
DOPMe	0.54 ± 0.19	4.4 ± 0.5	0.046	46.3	64.2
POPC
small	0.77 ± 0.13	20.0 ± 3.8	0.124	41.1	71.7
large	≈37§	2,800§	0.28§
diC7PC	0.31 ± 0.04	1.9 ± 0.1	0.058	45.4	65.4
POPC/POPA
POPC	0.40 ± 0.11	8.8 ± 1.4	0.122	41.2	71.5
POPA	0.48 ± 0.30	9.0 ± 1.7	0.048	46.2	64.4

diC₇PC, diheptanoylphosphatidylcholine; POPA, 1-palmitoyl-2-oleoyl phosphatidic acid.

^*All samples are 5 mM each phospholipid (1:1 for binary lipid vesicles) in 25% D₂O at 22°C.

^†The area ratio is the experimental area under the low-frequency dispersion curve, such as the curve in Fig. 2B divided by the sum of the area under the low- and high-frequency (the curve marked DP in Fig. 2C) dipolar dispersion curves.

^‡In calculating θ_PH from the area ratio, there are two possible magnitudes or roots depending on the assumed sign of the square root of (1/4)(3cos²θ_PH - 1)². The tabulated θ_PH(+) and θ_PH(-) are, respectively, these values for positive or negative signs of that root.

^§The rapid rise in relaxation rate prevented us from taking sufficient data to fit the relaxation profile as we did for the other samples. Instead, we estimated τ_v from the known size of these vesicles and fixed this parameter in the computer fit of the few points above baseline that we took. See Supporting Text for details.