Molecular Spectroscopy

Phenylhydrazine (PHZ), a potent chemical causes toxicity on various tissues at various levels. Administration of phenylhydrazine mainly causes haematotoxicity which leads to the haemolytic anemia. In mammals PHZ induced anemia increased the iron absorption in spleen, liver and duodenum and finally iron metabolism was altered. Local demand and supply of Fe would increase erythropoeitic activity of the spleen so the size of spleen was increased that create the splenomegaly. PHZ induced anemia activate immune response which triggers phagocytosis in the spleen and liver. Apart from this administration of PHZ interfere the binding of erythropoietin (EPO) with erythropoietin receptors (EPOR) so that JAK-STAT would be affected.PHZ also showed genotoxic effect by creating single strand DNA damage.

Quantitative determination of carbon isotopes using Laser Ablation Molecular Isotopic Spectrometry (LAMIS) is described. Optical emission of diatomic molecules CN and C2 is used in these measurements. Two quantification approaches are presented: empirical calibration of spectra using a set of reference standards and numerical fitting of a simulated spectrum to the experimental one. Formation mechanisms of C2 and CN in laser ablation plasma are briefly reviewed to provide insights for implementation of LAMIS measurements. A simulated spectrum of the 12C2 Swan system was synthesized using four constituents within 473.5‒476.5 nm. Simulation included three branches of 12C2 (1-0), branches R(0-0) and R(1-1), and branch P(9-8) of 12C2. Spectral positions of the tail lines in R(0-0) and R(1-1) were experimentally measured, since they were not accurately known before. The Swan band (1-0) of the isotopologue 13C12C was also simulated. Fitting to the experimental spectrum yielded the ratio 13C/12C = 1.08% in a good agreement with measurements by isotope ratio mass spectrometry. LAMIS promises to be useful in coal, oil and shale exploration, carbon sequestration monitoring, and agronomy studies.

Continuous wave (cw) distributed feedback (DFB) telecom diode lasers are increasingly being used as light sources in the near-IR regions of the spectrum for cavity ring-down spectroscopy (CRDS). They are compact, operate economically at room temperature, are able to generate suitable narrowband tunable coherent radiation on a single longitudinal mode and are compatible with a variety of optical components, including fibre-optic devices. The very high sensitivities enabling to measure weak absorption with cw CRDS plus the quantitative nature of the absorption measurements are enabling an expanding range of applications of cw CRDS in molecular spectroscopy, atmospheric chemistry, plasma and medical diagnosis.

Tracing measured compositions of comets to their origins continues to be of keen interest to cometary scientists and to dynamical modelers of Solar System formation and evolution. This requires building a taxonomy of comets from both present-day dynamical reservoirs: the Kuiper Belt (hereafter KB), sampled through observation of ecliptic comets (primarily Jupiter Family comets, or JFCs), and the Oort cloud (OC), represented observationally by the long-period comets and by Halley Family comets (HFCs). Because of their short orbital periods, JFCs are subjected to more frequent exposure to solar radiation compared with OC comets. The recent apparitions of the JFCs 9P/Tempel 1 and 73P/Schwassmann-Wachmann 3 permitted detailed observations of material issuing from below their surfaces—these comets added significantly to the compositional database on this dynamical class, which is under-represented in studies of cometary parent volatiles. This chapter reviews the latest techniques developed for analysis of high-resolution spectral observations from ∼2–5 μm, and compares measured abundances of native ices among comets. While no clear compositional delineation can be drawn along dynamical lines, interesting comparisons can be made. The sub-surface composition of comet 9P, as revealed by the Deep Impact ejecta, was similar to the majority of OC comets studied. Meanwhile, 73P was depleted in all native ices except HCN, similar to the disintegrated OC comet C/1999 S4 (LINEAR). These results suggest that 73P may have formed in the inner giant planets’ region while 9P formed farther out or, alternatively, that both JFCs formed farther from the Sun but with 73P forming later in time.

The design of a chirped-pulse Fourier transform microwave spectrometer operating in the 2–8GHz frequency range is presented. The linear frequency sweep is generated by an arbitrary waveform generator with a sampling rate of 20 GS/s. After amplification, the microwave pulse is broadcast into a vacuum chamber where it interacts with a supersonically expanded molecular sample. The resulting molecular free induction

In this paper we report on the laser-induced fluorescence spectra of indole, 3-methyl indole, and 3-indole acetic acid in pulsed supersonic expansions of He. The electronic origin of the first excited CL b) state is 35 233 cm-1 for indole, 34887 cm-1 for 3-methyl indole, and 34044 cm-1 for 3-indole acetic acid. On the basis of the energetics and fluorescence lifetimes, the spectral features at excess vibrational energies Ev = 0-2200 cm-1 for indole and Ev = 0-1600 cm-1 for 3-methyl indole were assigned to the vibrational level structure within a single electronic manifold. The second electronically excited CLa) state is not located in the above energy ranges. The energetics of selective solvation of 3-methyl indole was inferred from the spectra of the van der Waals complexes with Ar, H 2 0, and D 2 0, which provide information on microscopic solvent shifts of the electronic origin and of some prominent vibrational excitations of the I Lb states.