Relaxation mechanism of excited acridine in nonreactive solvents

Abstract

excitation is believed to involve the = 0 -*• 1 transition and thus is a measure of the fundamental vibration for the ion.3 Although ion-matrix electronic interactions are on the order of 1 eV,22 differences in interactions between ground and excited vibrational states are probably small, and vibrational spectra of matrix-isolated molecular ions are believed to be representative of the gaseous ion. The fact that argon-krypton matrix differences are small (5-7 cm"1) for such ions as CF3+ and CHBr2+, which are only slightly larger than the 4-cm'1 3argon-krypton matrix difference for CF3 and CHBr2 radicals,1,9,23,24 suggests that the gas-to-argon matrix shift for the vibrational fundamental of the ion is relatively small (~10 cm"1). This in turn suggests that even the low-intensity IRMPDS may involve higher vibrational manifold excitations and peak at slightly lower energy than the fundamental owing to normal cubic anharmonicity.Perhaps the most important information from the present study is that C-F vibrational modes in relatively large radical cations absorb at slightly higher frequencies than the corresponding modes of the neutral molecule. The effect on perfluoropropene is relatively small, ca. 29 and 17 cm"1 for the two modes. A much larger increase (21)

Photochemical Loss of Nitric Acid on Organic Films: a Possible Recycling Mechanism for NOx

“…As shown in Figure 3, nitrate does not absorb significantly to the red of ∼320 nm, and so the radiation transmitted by the 340 nm filter should not excite that molecule directly. However, as shown in Figures 1 and 3, both neutral and protonated acridine do absorb strongly in the 300-400 nm region (38). This suggests the interesting possibility that the long-wavelength deprotonation might be due to acridine acting as a photosensitizer (39), transferring energy to nitrate anion which then reacts.…”

A combined theoretical and experimental study on molecular photonics

“…This will extend the sensory abilities of the compounds. Acridine has been much investigated since the mid-twentieth century and many of its properties have been the subject of a number of monographs [12,37] and more recent original papers [see, e.g., [38][39][40][41][42][43][44]). We have included acridine in the list of compounds discussed here with the goal of analyzing the changes in their spectral-luminescent properties and photophysical processes depending on the nature of the substituent in position 9 of acridine.…”

Excited state relaxation of 9-(4-diethylaminostyryl)-acridine

“…Triplet state formation [11][12][13], excited state reduction [14,15], and relaxation between excited ππ * and nπ * states [11,[16][17][18] were reported for different acridine derivatives. The triplet state formation in some of acridines takes place very efficiently, however, it has already been reported [10] that there is no evidence of triplet state population of DSA dyes.…”

“…These states were found to play a crucial role in the excited state relaxation of some acridine derivatives [11,[16][17][18]. In most cases, the nπ * state of acridines is slightly higher than the ππ * state, however, it was also suggested that positions of ππ * and nπ * states in aprotic solvents may be inverted [12,20,21].…”