The universe (everything that exists) is expanding – its space and time, home to: planets, stars, suns, moons, black holes, galaxies, matter (quarks and leptons), neutrinos (dark and voids), energy, quasars, nebulas, interstellar energy, gas and I have no doubt, a lot more besides.
The sun’s solar activity creates a broad band of vibrations (magnetic radiations). The sun stays hot by atomic fission two light nuclei combine releasing vast amounts of energy that form heavier (by absorption) nuclei inside its core. These nuclear forces create continuous expansion which bursts forth releasing cosmic rays – solar radiation freeing, by eruption, escaping matter (mass, space, volume).
The core of the sun is so hot it changes hydrogen atoms to helium. This results in a freeing-up of high-energy cosmic rays, that release photons – energy carrying particles, atoms, and molecules, which, in the chaotic multitude, collide, energizing each other, causing further released photons to radiate out. This energy creates fusion, (two light nuclei combine – releasing vast amounts of energy) a reaction which is continuous.
An atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. The protons have a positive charge and the neutrons no charge at all. The electrons are attracted to the protons by the electromagnetic force and the protons and neutrons are attracted to each other by the nuclear force. There are many possible energy levels electrons can occupy therefore many colours of emitted light.
Nuclear fusion, of a light-element atom, produce longer wavelengths than x-rays, rays that become easily absorbed – able to release their energy. It is this energy that causes stars to shine giving white light, which is electromagnetic energy, in stars and supernovae, the primary process by which new elements are formed. Fusion in stars is a self-sustaining reaction.
Visible light suggest a rainbow giving us seven colours: violet, indigo, blue, green, yellow, orange and red. Similar to, colours produced by a beam of white light projected and refracted through a glass prism. Where each colour merges into the next other colours are produced. The various bands of colour are not equal.
On the blue side of the spectrum there’s violet, ultra violet, x-rays, gamma and nuclear waves on the red side infra-red and radio-waves. Electromagnetic waves are described by their wavelengths, frequency, and, by their photon-energy. The ultra-waves are short fractions of atoms long, whereas infa-red-waves can be as long as the universe.
As an artist paints his colours produce sensitive feelings and moods. Blue: depression and sadness; green: contentment and freedom; yellow, prepared for action and sickness, red: anger and war. Deeper feelings are felt with ultra violet light which produces: alertness, memory, emotion and cognitive performance. Whereas infra-red light waves reduce wrinkles and repairs skin.
A leaf is green because the leaf’s pigment-atoms absorb photons of all light energies except those that correspond to wavelengths of green light which reflect back into your eye. Put another way. A leaf is green by the arrangement of electrons in the atoms of that leaf that will absorb and re-emit photons of energies according to quantum laws. However, the green leaf you perceive is not just about wavelengths of light. The visual cortex of your brain has evolved not just through education and inherent human understanding to perform lots of corrections, correlations and feelings which has to do with what you think the leaf’s colour should be, cognitive knowledge gained through education, experience and aptitude.
Spectroscopy is the study of quantized energy – transfers between radiation and matter. Microscpectroscopy is spectroscopic studies on microscopic scales. The energy of light is directly related to its wavelength by the Einstein-Planck relationship.
[E] is the energy of the photon, [h] is Planck’s constant: 6.626 x 10-34 J∙s, [ν] is the frequency of the photon, [e] is the speed of light: 3.0 x 108 m/s, and [λ] is the wavelength of the photon.
The electromagnetic energy of a photon is inversely proportional to its wavelength = short wavelengths, or blue light, is higher in energy than the longer wavelengths of red light. Due to these energetic differences, photons with different wavelengths interact differently with molecules. In the ultra-violet region, electronic transitions are mainly observed. Namely, when a photon of the correct energy level is absorbed by a molecule the electron is excited to higher levels. For a photon to be absorbed, the energy of the photon must be exactly the same as the difference in energy between the ground state and the excited state to which the electron transfers. The energy levels of the molecules are due to the types of atoms and how they are bound to each other. Additionally, the shape of the molecule as well as its environment can also play a part in structuring the energy levels.
Fluorescence
After the electron has jumped to the excited state, it usually then decays by internal conversion to the lowest excited state. From there it can decay back to the ground state by a number of paths. The most common is a radiation less transition whereby the electron drops from the, excited state, to the ground state losing energy without the emission of a photon. However, when the electron drops from the state to the ground state with the emission of a photon, the process is called fluorescence. It is a rapid process and fluorescence life-times usually follow first order kinetic rules. Fluorescence intensity is governed by many factors, some include excitation wavelengths, fluorescence quantum yields, quenching factors, and even molecular structures.
Reflectance
Reflectance micro spectroscopy simply measures the spectra of electromagnetic energy reflected from the sample. The portion that is not reflected may have been absorbed – transmitted through the sample (if transparent to that wavelength of light) or even scattered. Reflected light may be divided into two types: specular and diffuse. Specular reflectance is like the reflectance from a mirror – the light is reflected at the same angle as it impinges upon the mirror’s surface. Diffuse reflectance is similar to that which occurs with white paper where light is effectively reflected at all angles.
Chemistry, Colour & Spectrophotographic Measurement
Substances absorb, reflect or emit light in ways that are dependent upon their chemical structure and their environment. Examples include the pigments found in paints or inks that reflect specific wavelengths of light which we perceive as a colour, quantum dots, commonly used for biological analysis, that emit light of specific wavelengths after excitation or testing the quality of printed matter. The optical properties of these colorants depend upon the molecular structure of their chromophores (the molecules that interact with the light) as well as their environment. Measuring the optical properties of these molecules on the microscale is called micro spectroscopy.
Colour Theory
Projected coloured light. A light box contains three projectors – each projector holds a primary light filter (red, green or blue), when these filters are projected onto a white screen and two of the lights overlap, say red and green, the result gives yellow; overlapping green and blue produces cyan and overlapping red and blue produces magenta. These colours: Yellow, Cyan and Magenta are the secondary colours of light that are used to reproduce, by printing, a coloured original. When photographic primary filter colours red, green and blue are all projected and overlapped black is the result, light is absorbed by all three colours. The overprinting of yellow, cyan and magenta also in theory produces black. That they do not is not a problem with the theory just a problem of poor printing ink pigments. Yellow printing ink has excellent spectral measurements, Magenta lacks blue and is weak and Cyan is by far the poorest lacking saturation (strength) The photographic filter colours are closer to perfection.
Links
http://www.openwindowslearning.co.uk/
https://www.earlyvictorianlife.co,uk/
https://www.kerryhistory.com/
Terence Kearey is hereby identified as the author of this written work and the pictures in accordance with Section 77 of the copyright, design and Patents Act 1988. All right reserved. No part of the publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or by any information storage and retrieval system, without permission in writing from the author.