TABLE 2.

Fluorescence decay of pyrene-1-COO⁻ in the presence of Na acetate and Na phosphate salts (aqueous solution pH 5, 20°C)

Conditions Concentration of Na salt	Analysis for exponential decay				Analysis for excited state reaction*
		λemis, nm	τi, ns	αi		k1, s−1	k2, s−1	A	B
0.1 M acetate	381	4.5, 19.5	−0.24, 0.76	1.031	2.6 × 107	3.8 × 107	0.90	0.096
0.1 M acetate	420	4.7, 19.3	−0.34, 0.66	1.045	2.4 × 107	1.2 × 107	0.92	0.08
0.5 M acetate	381	4.0, 9.4	−0.42, 0.58	1.005	1.1 × 108	4 × 107	0.80	0.20
0.5 M acetate	420	3.9, 9.4	−0.45, 0.54	1.049	1.2 × 108	4.8 × 107	0.87	0.13
1.0 M acetate	381	2.8, 7.51	−0.43, 0.57	1.001	2.2 × 108	6.7 × 107	0.75	0.25
1.0 M acetate	420	2.74, 7.47	−0.46, 0.54	1.051	2.2 × 108	6.5 × 107	0.82	0.18
2.0 M acetate	381	1.83, 6.7	−0.41, 0.59	0.993	4.1 × 108	8.8 × 107	0.70	0.30
2.0 M acetate	420	1.81, 6.63	−0.44, 0.557	1.038	4.1 × 108	9.2 × 107	0.74	0.26
0.5 M phosphate	381	4.5, 23.6	−0.21, 0.79	1.053	1.4 × 107	2.8 × 107	0.94	0.06
0.5 M phosphate	420	4.5, 23.5	−0.35, 0.65	1.04	1.5 × 107	4.4 × 107	0.96	0.04
1.0 M phosphate	381	3.7, 14.6	−0.34, 0.66	0.968	6.1 × 107	7.9 × 107	0.87	0.13
1.0 M phosphate	420	3.6, 14.6	−0.43, 0.57	1.000	6.0 × 107	7.0 × 107	0.89	0.11

^*Values for Γ₁ and Γ₂ obtained from the lifetime values given in Table 1 for pH values 2.0 and 9.4 at 20°C; A and B are defined by Eq. 7.