The spectrum of atomic hydrogen: A freshman laboratory experiment

The spectrum of atomic lithium. An undergraduate laboratory experiment

“…Ritz-Paschen (n -3) The series stemming from the m -1, 2, etc., levels are observed in different regions of the spectrum in the case of hydrogen; however, this is not generally true for atomic transitions. Two very important patterns observed in the Rydberg series of hydrogen, which also occur in atomic and molecular systems, are: (1) the spacing between successive lines decreases with decreasing wavelength and (2) a corresponding decrease in intensity occurs for n -1* m transitions as n increases with m fixed (5). In the hydrogen spectra (5 = 0) each series can be reproduced with the progression given by eqn.…”

“…Thus, this experiment is suitable for junior or senior students. It is based on a match of energy differences for all possible transitions in the spectrum to a table of Anm( 6) -[l/(m -<5)2] -[l/(nif] (1) for the case n = m + 1 with a constant quantum defect fi. In this presentation data from the visible spectrum of lithium (ns -* 2p and nd -* 2p transitions) are analyzed to demonstrate the technique; the analysis of the ultraviolet spectrum is left to the student. However, for completeness, sample data obtained by a student (enrolled in our Summer Institute in the Natural Sciences for Secondary School Teachers of Science) for the ultraviolet spectrum and its analysis are presented in Tables 4 and 5.…”

Atomic Emission Spectra Using a UV-Vis Spectrophotometer and an Optical Fiber Guided Light Source

“…The study of atomic emission spectra in the undergraduate laboratory has been suggested for many years to illustrate quantum mechanical principles (e.g., the idea that microscopic matter exists in quantized states) and the relation between the electronic structure and spectral observations (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11). Because of the simplicity of its spectrum, hydrogen is by far the element of choice in published experiments in atomic spectroscopy (1-5, 8, 10, 11), but experiments involving other elements such as alkali metals have also been reported (6,7,9).…”

“…Because of the simplicity of its spectrum, hydrogen is by far the element of choice in published experiments in atomic spectroscopy (1-5, 8, 10, 11), but experiments involving other elements such as alkali metals have also been reported (6,7,9). Several types of apparatus have been used to record the spectra, including an atomic absorption spectrophotometer (1), spectroscopes (2)(3)(4), spectrographs (5)(6)(7)(8) and UV-vis spectrophotometers (9)(10)(11). In all apparatuses of the latter type, the light source is either part of the spectrophotometer (deuterium lamp), yielding only a few lines (11), or when not a part, is placed inside the instrument (9,10) and is therefore difficult to interchange.…”

“…Several types of apparatus have been used to record the spectra, including an atomic absorption spectrophotometer (1), spectroscopes (2)(3)(4), spectrographs (5)(6)(7)(8) and UV-vis spectrophotometers (9)(10)(11). In all apparatuses of the latter type, the light source is either part of the spectrophotometer (deuterium lamp), yielding only a few lines (11), or when not a part, is placed inside the instrument (9,10) and is therefore difficult to interchange. This makes impractical the study of more than one element in a laboratory session.…”