Interest in the longer wavelength region of the electromagnetic spectrum has recently been spurred by research in electro-optics and materials science. Some of the techniques and hardware developed for those applications now allow fluorescence spectroscopy to stretch beyond the traditional boundaries of the ultra-violet and visible spectrum. One recent field of inquiry in IR fluorescence involves the characterization of solid-state laser materials such as Nd:YAG. In the photochemical area, singlet oxygen has been proposed as one of the primary intermediates of light-induced aging in polymers. Singlet oxygen is also of interest as a participant in certain biological mechanisms. As it happens both of these materials have major emissions in the region above one micron.

A picosecond fluorescence microscopy technique is applied to the liptinite maceral, alginite, of the Woodford Shale. Lifetime measurements indicate that two dominant fluorophores are responsible for the observed fluorescence. The lifetimes can be grouped into two characteristic ranges from 50 to 200ps and 500 to 900ps. There are indications that the higher rank (more mature) samples have shorter component lifetimes which may explain the lower fluorescence intensity witnessed with increasing rank. Continuous wave (c.w.) spectra are also given.

When materials are deformed and fractured, new surfaces are formed which may contain charge concentrations, defects, and broken bonds. The consequences of such departures from non-equilibrium can be the emission of particles (electrons, ions, and neutral species) as well as photons (triboluminescence). Collectively, we refer to these emissions as fracto-emission. In the case of peeling pressure sensitive adhesives from various substrates, charge separation plays a dominant role in producing relatively intense photon-emission as well as other emissions. Here we report on a few of the properties of the photon emission from peeling commercial adhesive tapes and address in particular the time, spectral, and spatial domains.

The phase behavior of phospholipid monolayers at a electrolyte/gas interface is studied by fluorescence microscopy. A Wigner lattice is observed at the LE/LC phase transition. Observation are quantified using digital image processing .These results show that the phase transition has three different regimes.

Laser excited phosphorescence spectra were used to probe the structure and energy transfer dynamics of molecules embedded in a polymer film. The systems studied consisted of 4,4'-dibromobenzophenone (DBP) and 4,4'-bromochlorobenzophenone (BCB) doped into polystyrene films. The processes of direct donor-acceptor energy transfer and spectral diffusion were investi-gated. From the donor-acceptor energy transfer kinetics, a fractal dimension of 2.4 was found to characterize the topology of the donor-acceptor system in the polymer matrix. For these experiments, the acceptor was 1,4-dibromonaphthalene. For BCB, aggregation occurs abruptly around a concentration of 12% by weight. This transition is reminiscent of percolation, and a statistical percolation-like model describes the concentration dependence of the aggregation process. Rapid spectral diffusion was found to occur in the aggregates at 4.2 K. The spectral diffusion appears to involve relaxation to low energy states in the interior of the aggregate, and energy transfer from molecules on the boundaries of the aggregate to discrete molecules outside the aggregate.

The rate of incoherent electronic excitation transport among chromophores randomly tagged on flexible polymer chains has been related theoretically to their ensemble average rms radius of gyration (<¹R 2>1/2). The rate of excitation transport is monitored by time-resolved fluorescence depolarization spectroscopy. Experiments which measure the rate of excitation transport among naphthyl chromophores in low concentration on iso-lated chains of poly-(2-vinylnaphthalene-co-methyl methacrylate) in poly(methyl methacry-late) (PMMA) host provide a quantitative determination of the copolymer <R 2>1/2. Measure-ments were made on copolymers of two different molecular weights and three different percentages of naphthyl containing monomers. In all cases, the measured <R 2>1/2 agree with determinations by other methods for PMMA in 6-solvents and are independent of 2-vinylnaphthalene concentration. The results demonstrate the utility of excitation trans-port techniques for quantitative investigation of polymer chain conformation in the solid state.

Drug abuse has become-one of the most compelling realities _ ot contemporary society. It has penetrated every segment ot our population: trom schools to sports and trom organized crime to board rooms . Drugs in tie w9rkplace allegedly cost government agencies and business millions ot dollars each year in increased absenteeism,. poor work performance, thefts,accidents andwastedtime. The President's Commission on Organized Crime and the federal government are in tavor ot urine drug testing. In fact many employers are now resorting to urine drug testing on current and prospective employees. This presep.tation discusses different laboratory methods used in urine drug.testing, including immunoassays, fluorescence polarization, thin layer chromatography, high pressure liquid chromatography, gas chromatography and gas-chromatography-mass spectrometry.

Fluorescence detection is in common usage in forensic science laboratories for the visualization of three enzyme markers. The fluorogenic substrates, 4-methylumbelliferyl phosphate, 4-methylutbel-liveryl acetate, and fluorecein diacetate, are acted upon by the enzymes Erythrocyte Acid Phospha, tase, Esterase-D, and Carbonic Anhydrase-III, respectively, to produce compounds visible to the analyst when viewed with transmitted UV light at 365 nm. Additionally, the choice of fluorogenic corn, pounds may help detect a specific enzyme from a related enzyme. One of the responsibilities of a forensic science laboratory may be the analysis of blood for genetically controlled polymorphic enzymes and protein markers. The genetic markers are said to be polymorphic because each exhibits types which can be differentiated and allows for the inclusion or exclusion of possible-donors of the blood. Each genetic marker can be separated into these recognizable types by electrophoresis, a technique which separates compounds based on electrical charges. Electrophoresis is conducted by placing a portion or extract of each bloodstain into a support medium which will conduct electricity. This is known as a plate or membrane. By controlling the pH of the buffer and the potential that is applied to the plate, the analyst can achieve separation of the types within an enzyme marker. The types appear as differing patterns of bands. Once the bloodstain has been subjected to electrophoresis, the enzymes must be visualized. This is generally best accomplished by using the specific activity of the enzyme. For the enzymes described in the present work, the visualization is performed by over-layering the plate with a piece of filter paper that 'has been saturated with the appropriate non-fluorescent substrate and buffer. The bands of enzyme, which is now in discrete patterns, will act upon the non-fluorescent substrate to create a fluorescent compound. The plate is then viewed with transmitted UV light at 365 nm to locate the band patterns which will identify the phenotype of the blood source. The plate should be photographed to record the findings.

Two fluorescent probes, ANS and TNS, have been further examined for their effectiveness in acting as fluorescent probes for the detection of blood stain patterns. These materials, which are not fluorescent in aqueous solution, react non-specifically with protein and enable an observer to discern a blood pattern when viewed under UV light at 365 nm. Other possible fluorescent probes have been evaluated and rejected for various reasons; these include luminol, tetramethylbenzidine, p-hvdroxy-phenylacetic acid, 3,4-dihydroxyphenylacetic acid, and 2,7-aminofluorene.

The compound tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate is suitable for laser detection of latent fingerprints on difficult surfaces such as wood and masking tape, as well as surfaces such as polyethylene, metal, etc. The fingerprint treatment can Involve either dusting with powder blended with this compound or by solution staining. The compound displays a strong d-n phosphorescence with a lifetime of about 10^-6 and is thus very well suited for time-resolved imaging to suppress background fluorescence.

The chiral and fluorescent complexes that are formed when bilirubin binds to three mammalian serum albumins [Human (HSA); Bovine, (BSA); and Rabbit, (RSA)] were studied using conventional fluorescence quenching, circular dichroism, fluorescence detected circular dichroism (FDCD), and FDCD quenching (FDCDQ). The fluorescence of the bilirubin complex with HSA at pH = 7.3 was quenched by the hydrophobic quencher 2, 2, 2-trichloroethanol yielding Stern-Volmer value of 2.89 M for traditional fluorescence quenching and 3.06 tel for FDCDQ. A Stern-Volmer value of 3.10 M was obtained using trichloroethanol as the quencher for the bilirubin-HSA complex at pH = 4.2. These results suggest that neither the addition of quencher to the system, nor the changes which occur upon acidification of the bilirubin-HSA complex change the microenvironment of the bound bilirubin fluorophore. The bilirubin complexes with BSA and RSA showed an increase in the fluroescence intensity upon the addition of trichloroethanol. Differences in the quenching of the mammalian serum albumin complexes by 2,2,2-trichloroethanol indicate a difference in the hydrophobicity of the microenvironment surrounding the bilirubin binding sites. Traditional fluorescence quenching measurements using triethylamine led to nonlinear Stern-Volmer plots for the bilirubin complexes with BSA and HSA. In addition, FDCDQ experiments detected large conformational changes in the bilirubin complexes with HSA and BSA when triethylamine was added. The fluorescence quenching and FDCDQ results with triethylamine may be interpreted to confirm previous bilirubin albumin studies which suggested that the bilirubin bound to one site on albumin produces a large Cotton effect with a small contribution to the fluorescence while the bilirubin bound to the second site on albumin produces intense fluorescence with a smaller contribution to the optical activity of the complex.

The techniques of Total Luminescence Spectroscopy and of Hole Burning are used to investigate the inhomogeneous and homogeneous linewidth of molecules in matrices at low temperatures. The principle of hologram storage with the hole-burning technique is outlined. Examples for laser-frequency selective and electric-field selective hologram storage are given.

Aerosol-OT (AOT) reversed micelles have been used to simultaneously enhance the fluorescence as well as the thermal lens effect in the analysis of solubilized lanthanide ions. The fluorescence is enhanced because the reversed micelles isolate and protect the analyte from quencher molecules while the thermal lens enhancement is due to the modification of the thermal physical properties of the solvent, i.e., increased dn/dT and decreased thermal conductivity values. Compared to that in water, AOT/CC14 reversed micelles increased fluorescence and thermal lens enhancement factors of TO+ by factors of 2 and 38, respectively. The mechanism for the fluorescence and thermal lens enhancement is discussed.

Phase-resolved total luminescence spectroscopy is described for the spectral finger-printing of three different crude oil samples in cyclohexane and in aqueous solutions of sodium taurocholate (NaTC) micelles. Phase-resolved spectra collected at three different excitation modulation frequencies are compared with steady-state spectra in order to illustrate the effects of fluorescence lifetime selectivity. Each phase-resolved spectrum represents a fluorescence lifetime "window" created by the adjustment of the detector phase setting to suppress scattered light, and the lifetime range of the spectrum is determined by the excitation modulation frequency.

Excitation dependent emission spectra from samples containing only a single chemical species are observed quite frequently, in particular at low temperatures. This is due to inhomogeneities in the sample solutions. From the point of view of chemical analysis this effect is rather tedious, since it mimics the behaviour of a multicomponent mixture. Some of the most abundant types of excitation dependence are reviewed using Total Luminescence Spectroscopy.

This paper presents the development and applidation of immunofluorescence spectroscopy in fiberoptics-based chemical and biological sensors. Focus is on a fluoroimmuno-sensor (FIS), which combines the excellent specificity of the antigen-antibody reaction and the high sensitivity of laser excitation and the versatility of fiberoptics technology. The FIS can detect 40 attomoles (10-18 mole) of benzo(a)pyrene tetrol, a DNA-adduct product of the carcinogen benzo(a)pyrene.

Four 7-alkyl-8-hydroxyquinoline-5 sulfonates were synthesized with the alkyl chain containing 6 to 12 carbon atoms. These compounds behave as Zwitterionic surfactants in neutral solution and as anionic surfactants in alkaline solution. More importantly, the o-hydroxyquinoline functionality is a versatile chelating group. Of the many metal complexes that it forms, several are fluorescent. Micellar media frequently have great effects on fluorescence properties; this is the first time fluorescence properties of such systems have been studied in conjunction with surfactant properties such as critical micelle concentration, etc. for systematically engineered lengths of the hydrocarbon tail.

The fluorescence spectrometry of 15 large polycyclic aromatic hydrocarbons (PAH's) were studied in nine solvents of widely varying properties. Trends in the Stokes shift, sharpness of spectral bands, and other features were correlated to solvent polarizability and other solvent properties.

A study was performed to show the effect of heavy atoms, matrices and a filler on the solid matrix room temperature luminescence of fluorescamine derivatized amino acids and drugs. Fluorescamine derivatized p-aminobenzoic acid (PABA), phenylpropanolamine hydrochloride (PPA) and alanine were used as model compounds for this study. Heavy atom species exhibited the following descending _order _of luminescence enhancement for the fluorescamine derivatized products: I > Br > Cl . The derivatized PABA showed more enhancement from heavy atoms than derivatized PPA or alanine. Derivatized PPA and alanine experienced equivalent heavy atom enhancement. Quenching was observed when AgNO, was used as the heavy atom for the phosphorescence measurement of fluorescamine derivatized products. Filler effects were observed by the addition of sodium acetate (NaAc) onto the solid matrices. Luminescence signals increased with increasing concentration of the filler. Matrices were observed to enhance the luminescence signal in the descending order of DE-81 > S&S 903 > P-81. It was found that the pH of a facile micellar solution enhanced the phosphorescence signal and decreased the rise time of a phosphor, such as biphenyl, naphthalene and pyrene. Attempts were being made to study the pH effect on the luminescence of aromatic acids. Compounds, 1- and 2-naphthoic acids were used for such a study. The effect of changes in pH of water and 0.05 M SLS solutions on fluorescence characteristics has been obtained for both acids. A weak phosphorescence signal of 2-naphthoic acid has been observed under certain conditions which needs further study. The pH of the solution, nonetheless, was found to drastically affect the fluorescence of 2-naphthoic acid.

Laser induced fluorescence and the sheath flow cuvette are combined to quantitate fluorescein in flowing streams. When combined with capillary zone electrophoresis, detection limits (3σ) are 1.8 attomole or 1 million molecules injected.

A miniature laser fluorescence system was developed as a low-cost, high-performance detector for capillary liquid chromatography. Using hybrid-microelectronic and optoelectronic devices to fabricate miniature electro/optic modules, a highly efficient measurement system was created. Detection limits for pyrene and perylene were determined to be about 500 fg and 10 fg, respectively, using less than 1 mW at 325 nm for pyrene and 13 MK at 442 nm for perylene. Significant improvements in performance will be achieved through more extensive use of the photon counting.

We have recently constructed an apparatus capable of measuring time resolved emission on a subpicosecond timescale following ultraviolet excitation. Using this equipment, it is possible to study many fundamental chemical processes in fluid solution. We have studied two aspects of the chemistry of polar solutions : microscopic solvation dynamics about polar dye molecules and fast intramolecular electron transfer. Microscopic solvation relaxation appears to be the rate limiting step in the intramolecular transfer reaction of the excited state of 9,9'-bianthryl.

Time-correlated photon counting technique has been applied to elucidate exciton dynamics in pyrene crystals. Transient free-exciton luminescence is observed at high temperatures as well as free-exciton luminescence associated with thefmalized free excitons. The self-trapping barrier height has been estimated to be 262 cm from the temperature dependence of the decay rate of the transient free-exciton luminescence. Also, luminescence due to unrelaxed self-trapped excitons is found at reduced temperature below the phase transition point, 120 K.

To extend hydrodynamic concepts to the molecular domain, and thus to use such concepts in the development of accurate rate theories for ultrafast chemical reactions, it must be realized that the relevant friction is a property, not of the solvent alone, but of the complete solute-solvent system. Properties of the solvent in the vicinity of reacting molecules are simply different than properties of the pure solvent. Because of this, a "renormalized" or effective friction must be introduced in place of the shear viscosity of the pure solvent. When this is done, hydrodynamic formalisms are found to be applicable to most experimental data. Past assumptions of "color blind" solvent-solute coupling seem to be the main reason that the moleculodynamic limit has been difficult to attain from the hydrodynamic starting point. A breakdown of ordinary hydrodynamics may still occur for very small (hydrogen-like) reacting particles because of the failure of the equilibrium assumption through the course of the reaction. Both computer molecular dynamics and ultrafast laser experiments are presented in support of these points of view.

Fluorescence lifetime data for rhodamine B in a series of normal alcohols have been measured as a function of-temperature, solvent polarity, and viscosity. Nonradiative rates for internal conversion have been extracted from this data. The solvent dependence of the nonradiative rates is discussed in terms of two activated barrier crossing models. In one model the activation energy is a linear function of the solvent polarity parameter ET(30). In another mode , the solvent dependence of the nonradiative rate is taken into ''t3- account by a viscosity ependent pre-exponential factor. Consistent results are obtained when a polarity-depend nt activation energy is used.

A simple picosecond time-resolved fluorescence spectrometer is developped using the optical Kerr effect. It allows to obtain whole time-resolved emission spectra between 4uuO and b000 Å. Applications to the study of conformational changes of solvent cage and intramolecular twisting in solutions of organic compounds are presented.

The dynamics of the intramolecular charge transfer reaction of p-dimethylaminobenzonitrile is examined in alcohol solutions. The rate of charge separation is faster than the solvent fluctuation rate, TEl. Comparison of the experimental results with a recent theoretical model by Nadler and Marcus suggests that the rate of charge transfer is controlled by fluctuations in the intramolecular vibrational modes, not solvent diffusion. In addition, the TICT emission is observed to undergo a time dependent Stokes shift. The spectral relaxation is examined and compared to dielectric continuum models of solvent relaxation.

Earlier we described two methods of reducing quenching effects in analytical luminescence measurements based on phase resolved spectroscopy (PRS). These methods are a form of time resolution based on the amplitudes and the phase shifts of modulated signals. In Method 1 the signal is modulated at a high frequency, and the ac signal is essentially independent of the degree of sample quenching. Method 2 simultaneously measures the modulated amplitude and the phase shift between the emission and the excitation; from these data one can correct the signal to that of the unquenched sample. A procedure is given for calculating the precision and accuracy of both methods for different noise levels and degrees of sample quenching. The merits of both methods are discussed. Method 1 is shown to have a lower noise level than Method 2, but suffers from systematic errors especially at low modulation frequencies. Method 2 is superior if lower modulation frequencies must be used and computational complexity and speed of response are less critical.

Organic photoconductors have found important applications in electrophotography. Many classes of materials, like phthalocyanines, squaraines, perylenes etc. have been used as charge generator layers in xerographic photoreceptors. And although numerous useful materials have been discovered, our knowledge of basic photoconductivity mechanisms in them has been limited. In recent years electric field induced fluorescence quenching emerged as a powerful tool to unravel details of the carrier generation mechanisms. In this paper we will review this work and also present new results on ClInPc in which a precise correlation between carrier generation efficiency measured spectroscopically and electrically is established.

The photoluminescence of three complexes of the type Zn(s-benzenethio1)2(2,9- dimethy1-1,10-phenanthroline) [s = F5, H, 4-MeO) has been investigated in EtOH glasses from 4.3 to 75 K. The pentafluoro molecule exhibits only inn* emission characteristic of the heterocyclic ligand, the methoxy compound displays a unique charge-transfer emission, but the unsubstituted complex displays both types of luminescence bands. The results are interpreted in terms of a barrier to energy migration in individual molecules that is a consequence of the near-degeneracy of two electronic configurations of widely disparate characteristics.

The diplatinate(II) pyrophosphite complex, K4[Pt2(P2O5H2)41, exhibit delayed fluorescence when it is excited to its triplet state. The decays of the delayed fluorescence observed at 1.2 K has been analyzed in terms of the annihilation of two triplet sublevels. Both the Eu-Eu annihilation and Alu -Aiu annihilation yield delayed fluorescence with the same spectral distribution.

Non-classical techniques, based on phosphorescence and delayed fluorescence, are applied to the study of chemical reactions in confined geometries and to the study of exciton fusion in disordered films, polymers and membranes. These techniques also characterize the topology, morphology and structure of molecular aggregates, strands, pores, and domain boundaries.

The rate of decay of triplet excitons following a photoexcitation pulse has been determined for poly(2-vinylnaphthalene) in a variety of solvents at ambient temperature and at 77 K. A three dimensional model for exciton diffusion fits the data at ambient temperature but at 77 K the data are not well represented by a single integral dimensionality.

The luminescence decay curves from crystals of two linear chain salts, (CH )4 NMnC13 (TMMC) and CsMnBr3(CMB), doped with exciton scattering as well as exciton trapping impurities Wre been investigated. In TMMC relatively small concentrations (1-5%) of Cd , a scattering impurity, dramatically reduce exciton trapping consistent, with expectations for highly one-dimensional systems. The effect of scattering impurities is much less dramatic in CMB where the exciton migration is clearly less one-dimensional. The lumines-cence decay curves from mixed crystals containing CsMnBr3 and CsMgBr3 or CsCdBr3 indicate that above 100K excitons percolate freely through the lattice at mole fractions of Mn2+as low as 0.1.

The feasibility of employing the peak shift of the fluorescence spectrum of rhodamine 6G in an ethanol solution as a time-resolved measure of pressure for shock wave studies is demonstrated for low stresses (below 20 kbar). The results of the shock experiments are in good agreement with previous hydrostatic measurements. No effects of temperature were observed in tests to 330 K under ambient pressure, or in the comparison of static and shock data. A time resolution of approximately 80 ns was achieved with a 100 μ.m thick sample, and using a cw Argon laser as the excitation source. Higher time resolution should be possible with pulsed excitation and a thinner sample cell.

We describe a polarization spectrophotometer capable of obtaining a continuous recording of a polarized emission spectrum as well as a polarized excitation spectrum. The instru-ment's optics were designed to separately detect each polarized component of the emission. The system utilizes an optical fiber bundle composed of two branches for signal mixing of each component and two lock-in amplifiers for separation of signals mixed and analyzed optically. Data acquisition and analysis were performed by a low-cost microcomputer equipped with an 8-bit analog-to-digital converter.

One or more solvent molecules have been added to selected derivatives of the amino acid tryptophan. The preparations are carried out using supersonic gas expansion techniques and the samples are probed via laser induced fluorescence spectra and fluorescence lifetime measurements. In tryptophan derivatives that have a polar side chain at the 3-indole position, the solvent complexes formed are different from those previously observed in indoles. Now it is the case that solvent adducts bind overwhelmingly at the polar sites of the 3-indole side chain and not directly on the indole. For at least one derivative, tryptamine, addition of a single water or alcohol molecule results in formation of one solvent-stabilized conformation independent of the starting conformation of the bare derivative molecule.