Table 1.

Energies and lifetimes of the S₁ (2¹A_g^-) excited states of geometric isomers of carotenoids.

carotenoid	τ₁^a (ps)	S₁ (2¹A_g^-) energy (cm^-1)		solvent	T (K)	Ref.

		S₁-S₂^b	Fluor.^c
all-trans-neurosporene
	34.8 ± 0.1	14,400 ± 50		EPA	77	this work
	23.0 ± 0.1	n.d.^d		acetone	RT	[26]
	25.5 ± 0.1	n.d.		CS₂	RT	[26]
	21.2 ± 0.1	n.d.		n-hexane	RT	[46]
	24.0	n.d.		n-hexane	RT	[75]
			15,300	n-hexane	RT	[45]
central-cis-neurosporene
	22.0 ± 0.1	14,950 ± 50		EPA	77	this work
all-trans-spheroidene
	11.5 ± 0.1	13,440 ± 20		EPA	77	this work
	7.8-8.5	13,400 ± 90		n-hexane	RT	[49]
	7.7-8.2	n.d.		n-hexane	RT	[31]
	8.7 ± 0.1	n.d.		hexane	RT	[47]
			14,200	n-hexane	RT	[45]
central-cis-spheroidene
	8.2 ± 0.1	13,840 ± 40		EPA	77	this work
13,14-locked-cis-spheroidene
	6.5 ± 0.1	n.d.		n-hexane	RT	[31]
15,15′-locked-cis-spheroidene
	7.1 ± 0.1	n.d.		pet. ether	RT	[31]
all-trans-spirilloxanthin
	2.0 ± 0.1	11,430 ± 30		2-MTHF	77	this work
	1.3	11,500 ± 200		n-hexane	RT	[76]
	1.4	11,530 ± 200		LH1	RT	[76]
	1.2 ± 0.2	n.d.		acetone	RT	[26]
	1.5 ± 0.1	n.d.		CS₂	RT	[26]
	1.7 ± 0.1	n.d.		EPA	77	[26]
	1.4	n.d.		hexane	RT	[52]
	1.3	n.d.		15% benzene in hexane	RT	[51]
	1.4	n.d.		THF	RT	[50]
	1.5	n.d.		benzene	RT	[53]
			11,900	n-hexane	RT	[77]
central-cis-spirilloxanthin
	1.7 ± 0.1	11,870 ± 50		2-MTHF	77	this work

Lifetime of the S₁(2¹A_g^-) excited state;

The value of the S₁(2¹A_g^-) excited state energy determined from the S₁-S₂ energy gap;

The S₁(2¹A_g^-) excited state energy determined from steady-state fluorescence;

not determined.