Emission Spectroscopy Blog Posts
7 Minute ReadIntroduction This post is to help the home experimenter identify the spectra of some common light sources that we all come across in the home. It gives us an indication of what to expect when we consider a light source for a particular application or whether we are simply curious about why some light sources […]
Common Light Sources in Your Home Read More »
6 Minute ReadIntroduction In two earlier posts on this site we recorded the absorption spectrum of molecular iodine I2 with some simple instrumentation. The first section outlined the basic theory giving rise to the vibrational absorption bands in the spectrum of any diatomic molecule. The second section described how the home experimenter can produce an absorption spectrum
The Fluorescence Spectrum of Iodine Read More »
4 Minute ReadIntroduction Spectrum tubes are a very useful way to introduce science students to the study of the interaction of light photons with matter and the subject of optical spectroscopy. They are often seen in demonstrations in high schools and early university lab classes to teach the basic principles of quantum theory and atomic and molecular
6 Minute ReadIntroduction Here is the emission spectrum of hydrogen gas in a discharge tube recorded at moderate spectral resolution: Fig. 1 The Spectrum of Hydrogen Gas in a Discharge Tube It was obtained, as with many other emission spectra on this blog, by using either a mini Tesla coil (widely available online) or a high voltage
The Hydrogen (and Deuterium) Emission Spectrum Read More »
9 Minute ReadIntroduction In this post the emission spectra of the Noble Gases are presented. The noble gases constitute the last group (Group 18) in the Periodic Table of the elements. Emission lines obtained from the spectra of these noble gases can be very useful for the calibration of a spectrometer. Historically, these elements were called the
Emission Spectra of the Noble Gases Read More »
3 Minute ReadIntroduction The above image is a sample of high purity caesium chloride crystals (CsCl). They are in a sealed glass ampoule and were prepared under high vacuum. At first glance, these appear to be fairly uninteresting plain white crystals, very typical of so many other inorganic and organic salts. But when these crystals are excited
Caesium Chloride and the F Centre Read More »
6 Minute ReadIntroduction The chemical element Selenium. Atomic number 34. Chemical symbol Se. The quirky title I chose for this post – an element that can’t make up its mind – refers to the fact that selenium is generally considered a nonmetal. However, it has also been classed, by many investigators in the past, as a metalloid.
Selenium: An element that can’t make up its mind Read More »
7 Minute ReadIntroduction Does anyone remember having glow-in-the-dark stars, planets and constellation stickers that as kids we would stick to our bedroom walls and ceiling? I don’t think I am the only one to remember and enjoy this daily night time event. Once the bedroom light was switched off these stickers would glow green for a while,
Phosphorescent Paints Read More »
7 Minute ReadIntroduction There are a number of technical constraints to consider when selecting a spectrometer for a particular application, whether this involves purchasing a commercial model from the wide range of relatviely low cost mini-spectrometers available these days, or whether one is designing and home-building a spectrometer from scratch. In this post we shall consider some
Factors Affecting Spectrometer Performance Read More »
3 Minute ReadThis is a quick post that examines the spectral line emission changes that occur when a Mercury-Argon (Hg-Ar) gas discharge lamp is switched on and warms up. I used the Time Acquisition mode of an Ocean Optics S2000 fibre-optic spectrometer to record the changes in intensity of 3 spectral lines after the lamp is switched
Mercury Lamp Spectral Changes at Start Up Read More »
