Radiation of energy

The energy of radiation at a given temperature is the integral of radiation density over all frequencies... 

The results of the theory of quantum mechanics require that nuclear states have discrete energies. This is in contrast to classical mechanical systems, which can have any of a continuous range of energies. This difference is a critical fact in the appHcations of radioactivity measurements, where the specific energies of radiations are generally used to identify the origin of the radiation. Quantum mechanics also shows that other quantities have only specific discrete values, and the whole understanding of atomic and nuclear systems depends on these discrete quantities. 

Show by a diagram why the energy of radiation emitted from an excited electronic state (by fluorescence or phosphorescence) is of lower energy than the exciting radiation. Would you expect the shift to lower energy to be more pronounced for fluorescence or phosphorescence Explain. 

The second contribution to the line-width is Doppler broadening. While the transition energy AE may be constant, the frequency and therefore the energy of radiation increases if the molecule is approaching the source and decreases if the molecule is receding from the source. In terms of energy... 

The deposited energy of radiation is spent mostly for ionization of liquid hydrocarbon molecules. During ionization, a pair of a cation radical (RH -) and an electron (e ) is produced as follows. 

A Equations 3.45 and 3.46 may be combined to give an equation for the molar quantum energy of radiation with a particular wavelength ... 

The energy of radiation is quite often expressed in terms of kilocalorie per mole (kcal/mole), (I calorie = 4-186 J). Sometimes, merely cm-1, the unit of wavenumber is used to express energy. The proportionality constant he, is implied therein. The unit of electron-volt (eV) is used for single atom or molecule events. A chemical potential of one volt signifies an energy of one electron volt per molecule. 

Some values for the energy of radiation in the visible and ultraviolet regions are given in Table 1.1. 

Let us assume that the system is in the lower state n and exposed to radiation of density p (v) defined as the energy of radiation per unit volun between the frequencies v and v + dv. The probability per unit time th it will absorb the radiation and will thereby be raised to the upper sta m, is proportional to the number of particles Nn in the state n and tl density of radiation of frequency vm . Hence... 

The bond between the two atoms of a diatomic molecule is characterised by a force constant of lOOON/m. This bond is responsible for a vibrational absorption at 2000 cm Accepting that the energy of radiation is transformed into vibrational energy, estimate a value for the length of the bond at the maximum separation of the two atoms. 

When the shock wave arrives at the photosphere, the bolometric luminosity reaches 2 xlO44 erg s-1 and the effective temperature becomes as high as 5 xlO5 K (Fig. 5) for Model 11E1. Hence, most of the radiation is emitted in the UV band. Total energy of radiation during the first two days amounts to 1047 erg, which is enough to ionize the circumstellar matter. 

The fundamental equation of quantum mechanics, Eq. (1), implies, on the one hand, that energy of radiation stays concentrated in limited regions 1393... 

An important reaction used quite widely for this purpose is irradiation by neutrons and measurement of die energies of radiations emitted. The source of the neutrons may be a nuclear reactor, a particle accelerator, or an isotopic source, that is, a sealed container in which neutrons are produced by alpha rays emitted by a source such as radium, sodium-24(24Na), yttrium-88f8sY), etc., and arranged so that the alpha rays react-with a substance such as beryllium which in turn emits neutrons. The neutrons react with stable nuclides in the sample to produce radioactive ones. Thus... 

Energy of radiation is quantized in photons, e = hv one photon excites one molecule to a higher energy state. 

The absorption spectrum of continuous thin film Ag is compared to that of Ag nanocrystals of much the same sizes as thickness of the film [17]. At high energy of radiation both spectra are practically identical, because absorption of such radiation results from interband transitions in metal [17]. 

The reactor for radiation chemical synthesis with an agitator (about 200 rotations per minute) is located in the operation chamber. Inside the reactor there is a cavity for introducing sources of y-radiation. The role of the radiation source is played by 60Co in airproof stainless steel ampules the activity of 60Co radiation is about 3000 eq Ra. The consumption degree of the energy of radiation when the sources are placed in the cavity, or the radiation coefficient of efficiency, varies from 17 to 19%. The equipment is encased in a special box made of stainless steel and plexiglass the box has intensive ventilation. 

Planck s constant was discovered as part of the solution to a nineteenth century conundrum in physics, known as the black-body problem. The challenge was to model the wavelength distribution of radiation emitted through the aperture in a closed cavity at various temperatures6. The standard equations of statistical thermodynamics failed to produce the observed spectrum, unless it was assumed that the energy of radiation with frequency v was an integral multiple of an elementary energy quantum hv. 

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