Ground state, of an atom

Adiabatic ionization. A process whereby an electron is removed from the ground state of an atom or molecule, producing an ion in its ground state. 

The selective ionization of EEPs is attained due to an ionization potential difference between the excited and ground states of an atom or a molecule, a difference that is equal to the excitation energy. Thus, the ionization potentials of oxygen states and Zj are 1.0 and 1.6 eV,... 

A unit of time (symbohzed by s) that serves as one of the seven base SI units, equal to the duration corresponding to 9,192,631,770 times the period for transition between the two hyperfine levels of the ground state of an atom of... 

The ground state of an atom is obtained by placing all available electrons in the orbitals in the order of increasing energy, following Hund s rule, when there are isoenergetic orbitals. An excited state is formed when one or several of these electrons are displaced to other orbitals. These states then correspond to one-electron or two-electron , etc., excitations, as illustrated in Figure 3.2. 

In Fig. 5.1 we show p(v) vs v at 300 K using both frequency and wavenumber as abscissae. A typical optical transition from the ground state of an atom has frequency v = 3x 1014 Hz, and a transition between two Rydberg states has frequency v 3x 1011 Hz. Thus, it is apparent from Fig. 5.1 that to a ground state atom the black body radiation appears as a slowly varying, nearly static field, whereas to a Rydberg atom it appears to be a rapidly varying field. 

The Aufbau principle states that in the ground state of an atom, the electrons occupy the lowest energy levels available. 

In order to interpret magnetic susceptibility data, it is necessary to know the ground state of an atom with more than one electron... 

The ground state of an atom is its normal, lowest-energy state. The excited state shown accounts for the bivalency of Be, but not for the equivalence of the two bonded atoms. 

The ground state of an atom may be chosen by application of Hund s rules. Hund s first rule is that of maximum multiplicity. It states that the ground state will be that having the largest value of 5, in the case of carbon the 3F. Such a system having a maximum number of parallel spins will be stabilized by the exchanf e energy resulting from their more favorable spatial distribution compared with that of paired electrons (see Pauli principle. Chapter 2). 

Hund s rules are inviolate in predicting the correct ground state of an atom. There are occasional exceptions when the rules are used to predict the ordering of excited stales. 

The ground state of an atom or a molecular species is the miniinum energy state of the species. At room temperature, most species are in their ground state. 

The ground state of an atom is its lowest possible energy state. 

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