Next lowest state

To define the state yon want to calculate, you must specify the m u Itiplicity. A system with an even ii n m ber of electron s n sn ally has a closed-shell ground state with a multiplicity of I (a singlet). Asystem with an odd niim her of electrons (free radical) nsnally has a multiplicity of 2 (a doublet). The first excited state of a system with an even ii nm ber of electron s usually has a m n Itiplicity of 3 (a triplet). The states of a given m iiltiplicity have a spectrum of states —the lowest state of the given multiplicity, the next lowest state of the given multiplicity, and so on. 

IlyperChcm semi-empirical methods usually let you request a calculation on the lowest energy stale of a given multiplicity or the next lowest state of a given spin m ultipliriiy. Sin ce m osl m olecu les with an even num her of electron s are closed-shell singlets without... 

Single-ion nonradiative decay for Ln3+ diluted into transparent host elpa-solite crystals, where the energy gap is greater than the Debye cutoff, is primarily due to multiphonon relaxation (with rate kmp). In some cases, first order selection rules restrict phonon relaxation between states, such as between Tig and T4g, or between T2g and T5g, CF states for MX63- systems. The dependence of the multiphonon relaxation rate, kmp, upon the energy gap to the next-lowest state (AE) has been investigated for other systems and is given by a relation such as [353, 354]... 

Figure 5.20 A simple transi-Hon from the lowest state to the next-lowest state would result in a sharp transition at the wavelength of light with energy equal to the energy gap. In reality, the transitions are rarely that simple and result in band broadening. 

This dialog box also contains the option for specifying that the molecular system ism the first excited singlet stale (Next lowest or the Lowest electronic state. 

Request either the lowest energy state of the specified multiplicity or the next lowest energy state for semi-empirical calculations. 

Figure 1 shows the energy of the lowest electronic state as the interatomic distance is varied. The energy of the next lowest electronic... 

The situation for 172 was quite similar, but trends between conformers were reversed the solid-state conformer (chair-chair-boat) corresponded to the minor solution isomer of 184, whereas the minor solution isomer of 172 corresponded to the major all-chair conformer of 184. Imakura s desethano artemisinin 171 was found to exist in the all-chair arrangement by X-ray and exhibited a nontempera-ture-dependent proton NMR spectrum. MM2 studies of 171 showed that the all-chair conformer was 4-5 kcal/M more stable than the next lowest energy conformer, a chair-chair-boat, and were thus consistent with experimental observations. Studies to correlate conformer populations and energetics with antimalarial activities have not provided clear answers.141... 

Considering the simplest carbene, methylene, it is clear that it could have a linear structure (D -symmetry) or be bent ((72s-symmetry). In the former case, using the ls-orbitals of hydrogen and the 2s- and 2 -orbitals of carbon, two a molecular orbitals can be constructed and these can clearly accommodate the C—H bond electrons. A degenerate pair of orbitals, similar to carbon atomic p-orbitals, are the ones of next-lowest energy. The linear structure of methylene would thus correspond to a triplet state. 

Next the absorption spectrum from the ground state was also calculated and compared with the experimental spectrum (Kollia et al., 1995). Since the latter was measured at room temperature, we considered not only the lowest state at 0 eV (T7.8) but also the first excited level at 0.0164 eV (1 8) and the second-excited level at 0.0226 eV (Ts ). 

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