Luminescence of nitroaromatic molecules

Khalil, Omar S.; Bach, Hermann; McGlynn, S. P.

doi:10.1016/0022-2852(70)90186-4

Cited by 44 publications

(29 citation statements)

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“…It is found that (Ermolaev and Svitashev, 1959) Of < 0.0001 and Φρ = 0.083 relative to a quoted (Gilmore et al, 1952) Of = 0.55 for naphthalene. only phosphorescence in standard organic glasses (Corkill and Graham-Bryce, 1963) and exhibit only fluorescence in acidic glasses (Khalil et al, 1970). Í As given by McClure (1949).…”

Section: -And 2-nitronaphthalenes: Emission Spectramentioning

confidence: 95%

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Luminescence Characteristics of Polar Aromatic Molecules

1974

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Section: -And 2-nitronaphthalenes: Emission Spectramentioning

confidence: 95%

“…Distilled samples of nitrobenzene phosphoresce whereas GLC-purified samples do not (de Mayo, 1970). The emission, therefore, is probably spurious (Khalil et al, 1970). The molecules p-nitrotoluene, p-chloronitrobenzene, p-nitroanisole.…”

Section: Nitrobenzene: Molecular Luminescencementioning

confidence: 99%

Luminescence Characteristics of Polar Aromatic Molecules

1974

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“…Phosphorescence occurs from the triplet π,π* state (primarily located on the aromatic system), which in this case is lower in energy than the triplet n,π* state. For nitroarenes with extensive aromatic systems (such as 6-nitrochrysene), the singlet π,π* state becomes lower in energy than the singlet n,π* state, which allows fluorescence to occur in addition to phosphorescence (Khalil et al 1970). This situation is shown at the right of Figure 6.…”

Section: Nitroarenesmentioning

confidence: 89%

“…The center diagram in Figure 6 gives the Jablonski diagram for a nitroarene with a slightly larger aromatic system-for example, 1-nitronaphthalene. As in nitrobenzene, no fluorescence occurs because of the dominance of the nonradiative ISC; however, phosphorescence is observed at 77 K (Khalil et al 1970). Phosphorescence occurs from the triplet π,π* state (primarily located on the aromatic system), which in this case is lower in energy than the triplet n,π* state.…”

Section: Nitroarenesmentioning

confidence: 96%

“…The following discussion will distinguish between two types of photoluminescence: 1) fluorescence, which is a transition occurring from the lowest excited singlet state to the ground singlet state, and 2) phosphorescence, which refers to a formally forbidden transition from the lowest excited triplet state to the singlet ground state (Lower and El-Sayed 1966). Most nitroarenes are known to lack fluorescence (Khalil et al 1970;Ohtani et al 1980), but some of them can show weak phosphorescence, especially at cryogenic temperatures. Nitroarenes exhibit fluorescence only if the aromatic system is large.…”

Section: Nitroarenesmentioning

confidence: 99%

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Studies of the laser-induced fluorescence of explosives and explosive compositions.

Hargis¹,

Thorne²,

Phifer³

et al. 2006

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Continuing use of explosives by terrorists throughout the world has led to great interest in explosives detection technology, especially in technologies that have potential for standoff detection. This LDRD was undertaken in order to investigate the possible detection of explosive particulates at safe standoff distances in an attempt to identify vehicles that might contain large vehicle bombs (LVBs). The explosives investigated have included the common homogeneous or molecular explosives, 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), cyclonite or hexogen (RDX), octogen (HMX), and the heterogeneous explosive, ammonium nitrate/fuel oil (ANFO), and its components. We have investigated standard excited/dispersed fluorescence, laserexcited prompt and delayed dispersed fluorescence using excitation wavelengths of 266 and 355 nm, the effects of polarization of the laser excitation light, and fluorescence imaging microscopy using 365-and 470-nm excitation. The four nitro-based, homogeneous explosives (TNT, PETN, RDX, and HMX) exhibit virtually no native fluorescence, but do exhibit quenching effects of varying magnitude when adsorbed on fluorescing surfaces. Ammonium nitrate and fuel oil mixtures fluoresce primarily due to the fuel oil, and, in some cases, due to the presence of hydrophobic coatings on ammonium nitrate prill or impurities in the ammonium nitrate itself. Pure ammonium nitrate shows no detectable fluorescence. These results are of scientific interest, but they provide little hope for the use of UV-excited fluorescence as a technique to perform safe standoff detection of adsorbed explosive particulates under real-world conditions with a useful degree of reliability. LDRD Studies of the Laser-Induced Fluorescence of Explosives and Explosive Compositions4

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Photothermal Studies of Photophysical and Photochemical Processes by the Transient Grating Method

Terazima

1998

Advances in Photochemistry

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Luminescence of nitroaromatic molecules

Cited by 44 publications

References 1 publication

Luminescence Characteristics of Polar Aromatic Molecules

Luminescence Characteristics of Polar Aromatic Molecules

Studies of the laser-induced fluorescence of explosives and explosive compositions.

Photothermal Studies of Photophysical and Photochemical Processes by the Transient Grating Method

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