摘要: A structureless fluorescence with a half‐width of ∼6.5 kK has been observed from optically excited alkylated acetylenes (from propyne to 1‐, 2‐, 3‐, and 4‐octynes) in cyclohexane solution. The emission maxima the 1‐alkyne series (propyne, 1‐butyne, 1‐pentyne, etc.) are all at 370 nm, those 4‐alkyne (2‐butyne, 3‐hexyne, 4‐octyne, 388 regardless number carbon atoms, NC, molecule. is subject concentration quenching efficiency which much higher for 1‐alkynes than 4‐alkynes. fluoresence quantum yields, extrapolated zero concentration, 4‐alkynes found be independent 0.013, 0.014, 0.009, respectively. spectra vapor phase very similar solution except slight blue shift (by ∼5 nm). emissions interpreted as originating lowest singlet states (?) alkynes, ...