Applied laser spectroscopy-techniques and trends

Modern research in atomic and molecular spectroscopy is mainly based on applications of lasers as spectroscopic sources. This has led to revolutionary advances, not only in fundamental spectroscopy studies, but also in techniques of applied spectroscopy in a variety of fields like analytical spectroscopy, atomic and molecular physics, chemical dynamics, surface studies, plasma physics, cosmology, biophysics and so on. In this article some of the applied aspects of laser spectroscopy are presented. Areas like laser- enhanced ionization spectroscopy, resonance multiphoton ionization, spectoscopy of discharges and flames, supersonic beams, and laser-ablated metal vapour spectroscopy are illustrated with reference to the current techniques and future trends

Adsorption of CO on NaZSM-5 zeolite under moderate temperature and pressure conditions: an FTIR investigation

Adsorption of CO on NaZSM-5 zeolite was investigated at temperatures in the range 300-470 K and at pressures of 5-500 Torr using FTIR spectroscopy. The effect of exchanging the charge balancing cation in NaZSM-5 with a proton or calcium was evaluated. Data were also collected on NaY, CaY and CaX zeolites for comparison. We detected the development of six distinct CwO stretching bands with maxima at around 2111, 2130, 2146, 2160, 2176 and 2194 cm-1 during the adsorption of CO on NaZSM-5 zeolite at ambient temperatures. This was accompanied by the appearance of a prominent band at 2356 cm-1 and weak shoulder bands at frequencies around 2336, 2340, 2370 and 2380 cm-1 in the ν3 region of All the ν(CO) bands and CO2 . also the bands in the ν3 region of CO2 exhibited similar behaviour as a function of adsorbate pressure, evacuation, rise in sample temperature, and the exchange of charge balancing cation. For instance, the intensity of all the CwO stretching bands showed a similar growth behaviour with increasing adsorbate pressure, though the extent of this growth was di.erent for the individual IR bands. Similarly, these bands were removed simultaneously on evacuation. Furthermore, while all the vibrational bands in the v(CO) region showed a uniform isotopic shift corresponding to a frequency ratio ν(13C/12C) of ca. 0.977 and ν(18O/16O) of 0.976 for the adsorption of 13C16O and 12C18O, respectively, the bands in the ν3(CO2) region showed a red shift ?(13C/12C) of 0.972 with 13CO and an isotopic shift corresponding to 16O12C18O on 12C18O adsorption. No shift in ν(OH) bands was observed after CO adsorption under the conditions of this study. The results thus indicate that the individual zeolitic surface sites e.g., the Al3+ sites, Bronsted acid sites or the charge balancing cations, may not participate directly in the bonding of CO molecules at room temperature or above. Instead, the cage effect of zeolites plays an important role. The data are interpreted to suggest the formation of weakly bonded clusters of CO and CO2 molecules, occluded in the zeolitic cages and stabilized under the cationic field

The vibrational analysis of cyclopentanone

The infrared and Raman spectra of cyclopentanone, ααα'α'-d4-cyclopentanone, βββ'β'-d4-cyclopentanone and dB-cyclopentanone have been measured and a normal co-ordinate analysis performed based on a twisted C2, conformation. The 36 normal vibrations were computed using a selective valence force field comprising 16 diagonal and 16 off-diagonal force constants. The 4 isotopic species provided 144 frequencies to refine 15 diagonal force constants. The initial values of the constants were transferred from a force field for cyclohexanone computed in this laboratory. The infrared and Raman spectra were analyzed in terms of the potential energy distribution coefficients categorized as group frequencies, zone frequencies, and delocalized frequencies

Measurements of plasma temperature and electron density in laser-induced copper plasma by time-resolved spectroscopy of neutral atom and ion emissions

Plasma produced by a 355 nm pulsed Nd:YAG laser with a pulse duration of 6 ns focussed onto a copper solid sample in air at atmospheric pressure is studied spectroscopically. The temperature and electron density characterizing the plasma are measured by time-resolved spectroscopy of neutral atom and ion line emissions in the time window of 300-2000 ns. An echelle spectrograph coupled with a gated intensified charge coupled detector is used to record the plasma emissions. The temperature is obtained using the Boltzmann plot method and the electron density is determined using the Saha-Boltzmann equation method. Both parameters are studied as a function of delay time with respect to the onset of the laser pulse. The results are discussed. The time window where the plasma is optically thin and is also in local thermodynamic equilibrium (LTE), necessary for the laser-induced breakdown spectroscopy (LIBS) analysis of samples, is deduced from the temporal evolution of the intensity ratio of two Cu I lines. It is found to be 700-1000 ns

Utilization pattern of child health care services in the rural area of Surendranagar district: a community based cross sectional study

Background: Infant and child mortality continues to be a major public health problem all over the country. Despite the existence of national programmes for improving child health in India, child mortality and morbidity continue to be high. Utilization of child health care services is poor in the rural areas, causing significant impact on the health causing increased morbidity and mortality.Methods: It was a Community based Cross-sectional study carried out in the rural area of Surendranagar district through oral questionnaire method which was pre-designed and pretested. Data on demography, history of colostrum, initiation of breastfeeding, prelacteal feeds, exclusive breastfeeding, introduction of complementary feeding, immunization, respiratory infections etc. were collected, compiled and analyzed by applying appropriate tests using SPSS.Results: Out of 154 participants, 43.51% were offered breastfeeding within one hour of birth. Association was observed between initiation of breastfeeding, exclusive breastfeeding, time of introduction of complementary foods and duration of breastfeeding and utilization of health education services. Educational level of mothers and immunization status of the children had a significant statistical association. The overall prevalence of ARI was 31.82% & of Diarrhoea was 39.61%.Conclusions: A positive association was observed between nutritional status and utilization of nutritional services. Significant impact of health education services given during the antenatal period was observed on initiation of breastfeeding as well as exclusive breastfeeding. Although child services in India have been created, strengthened and expanded over the years, their performance in terms of utilization particularly in rural area is still limited

Laser Raman spectroscopic studies on the interaction of drug Dapsone with model membranes

Amphiphilic molecules like model membranes exhibit several special properties because of their ability to undergo co-operative aggregation in aqueous systems. The special properties of such aggregates have made them very important in several applications in industry, basic sciences and advanced technology. To understand the interaction of these systems at a molecular level it is necessary to study several processes. Laser Raman spectroscopy is a convenient technique for gaining information at a molecular level on such systems. In the present paper the applications of laser Raman spectroscopy for the study of these systems are discussed with particular reference to the changes in conformation, identification of structural groups involved in various interactions, arrangement or packing of the amphiphiles in the solid, gel or solution phase, and the effect of additives

Spectroscopy of laser-produced plasmas: setting up of high-performance laser-induced breakdown spectroscopy system

It is a well-known fact that laser-induced breakdown spectroscopy (LIBS) has emerged as one of the best analytical techniques for multi-elemental compositional analysis of samples. We report assembling and optimization of LIBS set up using high resolution and broad-range echelle spectrograph coupled to an intensified charge coupled device (ICCD) to detect and quantify trace elements in environmental and clinical samples. Effects of variations of experimental parameters on spectroscopy signals of copper and brass are reported. Preliminary results of some plasma diagnostic calculations using recorded time-resolved optical emission signals are also reported for brass samples

QENS and FTIR studies on binding states of benzene molecules adsorbed in zeolite HZSM-5 at room temperature

Fourier-transform infrared (FTIR) spectroscopy and quasi-elastic neutron scattering (QENS) were employed for monitoring of the binding states of benzene molecules, adsorbed in HZSM-5 zeolite at 300 K and for loadings of 0.6 to 7 molecules per unit cell. While the in-plane combination C-C and C-H stretching bands of adsorbed benzene remained una.ected, a splitting was observed in the out-of-plane C-H bending vibrational bands, a feature reported for the transformation of benzene from liquid to solid phase. Also, the intensity ratio of the in-plane C-C stretching band (ν19 of adsorbed benzene at 1479 cm-1 and the bands in the region ) 3100-3035 cm-1 due to fundamentals and combination C-C and C-H stretching vibrations indicated a trend observed typically for a condensed phase of benzene. No shift was observed in the frequency of the above-mentioned IR bands when zeolite samples exchanged with Na+ or Ca2+ were employed. QENS results suggest that the benzene molecules occluded in zeolitic pores (~3 molecules per unit cell) undergo a 6-fold rotation but their translation motion is too slow. Also, a high residence time of 16.5 ps was observed for the benzene entrapped in HZSM-5, compared to a time of ~2.5 ps reported for the liquid and ~19 ps for the solid state of benzene. These results reveal again the compression of the benzene molecules on adsorption in zeolitic pores. It is suggested that the benzene molecules confined in cavities experience a strong intermolecular interaction, giving rise eventually to their clustered state depending on the loading. In the clustered state, benzene molecules are packed with their plane parallel to zeolitic walls and interact with each other through p-electron clouds. No electronic bonding is envisaged between these clusters and the framework or the extra-framework zeolitic sites

Violence against women: a study on nature, prevalence and extent

Background: To study the nature, prevalence and extent of domestic violence against women in the study area.Methods: The cross-sectional study was carried out in the urban and rural area of Surendranagar district of Gujarat. Total 600 ever married women of 15-49 years of age were selected for the study purpose. The self-administered questionnaire was used to gather all the information. Steps were taken up to maintain confidentiality.Results: Out of total 600 women, 231 (38.5%) were victims of domestic violence in one form or the other. The analysis based on each form of violence discloses that about 83% were victims of psychological violence, about 54% of the victims had experienced physical violence, about 32% were victims of economical violence and about 24% were victims of sexual violence.Conclusions: Husband was the frequent instigator of domestic violence. Psychological violence is the commonest form of violence experienced by the victims