Now showing items 1-10 of 10
| Abstract: | High resolution optogalvanic spectrum of the (11, 7) band in the first positive system of nitrogen molecule has been recorded from 17179 to 17376 cm- 1. Assignment of 432 rotational lines belonging to the 27 branches of this band has been carried out. |
| URI: | http://dyuthi.cusat.ac.in/purl/2446 |
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| Dyuthi-P0307.pdf | (304.6Kb) |
| Abstract: | Doppler limited high resolution spectrum in the wavelength region 17224 to 17236 cm−1 of the first positive system (B 3Π g −A 3Σ u + ) of the N2 molecule is recorded by optogalvanic spectroscopic technique using a single mode ring dye laser. It is observed that the intensity and line width of the rotational line increase with the discharge current. Dependence of the collision broadening coefficient on the current was also evaluated. |
| URI: | http://dyuthi.cusat.ac.in/purl/2637 |
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| Dyuthi-P0196.pdf | (533.5Kb) |
| Abstract: | The changes in emission characteristics of a neon hollow cathode discharge by resonant laser excitation of 1s 5→2p 2 and 1s 5→2p 4 transition have been studied by simultaneously monitoring the optogalvanic effect and the laser induced fluorescence. It has been observed that resonant excitation causes substantial variation in the relative intensities of lines in the emission spectrum of neon discharge. |
| URI: | http://dyuthi.cusat.ac.in/purl/2633 |
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| Dyuthi-P0192.pdf | (328.6Kb) |
| Abstract: | Observation of laser induced two-photon photoemission optogalvanic (TPPOG) effect from tungsten electrode in a discharge cell using 564 nm radiation obtained from a pulsed dye laser is described. The magnitude of the POG signal is studied as a function of laser energy under various discharge parameters. Competition between one-photon and two-photon processes has been observed when nitrogen gas is used in the discharge cell. |
| URI: | http://dyuthi.cusat.ac.in/purl/2492 |
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| Dyuthi-P0296.pdf | (201.4Kb) |
| Abstract: | Laser-induced photoelectric and photoemission optogalvanic effects in a Ne-Nd hollow cathode discharge have been studied using a continuous wave laser source. The potential barrier for photoinduced electron emission from the cathode decreases as the applied voltage is increased. Owing to secondary electron emission in the plasma, the photocurrent is greater than that without discharge. The multiplication of secondary electrons and the quantum efficiency are also investigated. |
| URI: | http://dyuthi.cusat.ac.in/purl/2579 |
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| Dyuthi-P0139.pdf | (320.5Kb) |
| Abstract: | The photoemission optogalvanic (POG) effect has been investigated in a neon-neodymium hollow cathode discharge using cw laser excitation. Both positive and negative effects were observed. It was found that the amplitude of the POG signal was unstable near the instability region of the discharge. |
| URI: | http://dyuthi.cusat.ac.in/purl/2448 |
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| Dyuthi-P0309.pdf | (372.7Kb) |
| Abstract: | A two-photon induced photoemission optogalvanic effect which brings about a change in the discharge voltage when a pulsed dye laser beam is focused on a tungsten electrode has been described. The experiment is performed with N2, NO2 and Ar discharges. The magnitude of the signal voltage is studied as a function of laser energy and discharge current. The effective quantum efficiency in the discharge is found to be larger than that in the vacuum condition. |
| URI: | http://dyuthi.cusat.ac.in/purl/2437 |
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| Dyuthi-CPG48.pdf | (188.4Kb) |
| Abstract: | A two-photon induced photoemission optogalvanic effect which brings about a change in the discharge voltage when a pulsed dye laser beam is focused on a tungsten electrode has been described. The experiment is performed with N2, NO2 and Ar discharges. The magnitude of the signal voltage is studied as a function of laser energy and discharge current. The effective quantum efficiency in the discharge is found to be larger than that in the vacuum condition. |
| URI: | http://dyuthi.cusat.ac.in/purl/2442 |
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| Dyuthi-P0303.pdf | (183.8Kb) |
| Abstract: | Electrical gas discharges have been the subject of numerous investigations from the last century due to their growing interest in technological and fundamental applications. Absorption of electromagnetic radiation by a gas discharge result into a change in electrical impedance due to a significant perturbations in the steady state population of excited levels and the degree of ionization. This change in impedance produced by resonant absorption of radiation is known as optogalvanic COG) effect. where as that is produced by injecting electrons in to the discharge by photoelectric emission is usually known as photoemission optogalvanic (FOG) effect. With the development of lasers and sophisticated electronic equipment. these effects have established their importance in analytical and spectroscopic measurements. The present thesis deals with the work carried out by the author in the field optogalvanic effect during the past few years at the Department of Physics in Cochin University of Science| and "Fechnology. The results and the observation are summarized in nine chapters and the references to the literature is made at the end of each chapter |
| Description: | Department of Physics. Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3814 |
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| Dyuthi-T1745.pdf | (3.988Mb) |
| Abstract: | We report the experimental observation of subcritical Hopf bifurcation and the existence of non-oscillating “windows” in the dynamics of a Ne-Nd hollow cathode discharge current as the control parameter. |
| URI: | http://dyuthi.cusat.ac.in/purl/2581 |
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| Dyuthi-P0141.pdf | (265.0Kb) |
Now showing items 1-10 of 10
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