Low-energy isomers

Figure 1. Low-energy isomers of Na(3p)Arn clusters, obtained on the lowest 3p PES. Isomers labeled (a) are global minima, isomers (a ) have higher energies.

Figure 3. Low-energy isomers of Na(3p)Ar elusters obtained on the seeond (b) and third (e) 3p potential energy surfaees.

Table 1. Computed cohesive energies (PWB 88) and mobilities of low-energy isomers for Sin (n < 20) neutrals, cations, and anions vs. measured mobilities (in He at 298 K, Ref. [16,44]), and calculated binding energies for Si + vs. CID data (Ref. [20]). Global minima are in bold. Multiple features observed for Sin cations (n > 17) are ranked by decreasing abundance.

Figure 8. Photoelectron spectra for Si (n = 8-20), experiment (bold) and LDA simulations for the global minima (Ref. [22]). For Sin, we show modeling for three low-energy isomers.

Glucose is a system in which the conformational average of multiple low energy isomers cannot be ignored. That is, the free energy of solvation is a Boltzmann probability-weighted average over conformations ... 

Fig. 1.16. The graph presents a comparison of theoretical and experimental vertical electron detachment energies (VDEs) for Aun in = 4-14). The optimized ground state structures (labeled A for each size) and close lying low-energy isomers are also displayed [120]. A change from planar geometry to SD-structural motifs is apparent between Aui2 and Auis ...

In a preliminary report Schleyer, Thiel, and coworkers also describe some calculations on structural isomers of perlithioethane 12. Of the seven calculated structures the low energy isomers, 12a (C h symmetry), 12b (D4h symmetry), and 12c (Cj symmetry), are candidates for the global energy minimum in the gas phase. In the solid state, however, C Li should aggregate and might exhibit consequent structural modification. 

Eight isomers of the crown-shaped Ss ring below the radical formation ( 150 kJ mor ) and several interconversion pathways of low energy isomers... 

Water clusters have been studied extensively both experimentally and theoretically over the past two decades. Among the issues that have been addressed are the geometrical structures of the low-energy isomers [1-19], the role of cooperative effects in the bonding [20-26], the sensitivity of the vibrational and rotational spectra on the H-bonding arrangements [27-36], the dynamics of isomer interconversion [37-39], and the finite temperature behavior of the clusters [39-47]. 

Fig. 17 Optimized geometries (bond lengths in angstrom and bond angles in degree) and relative energies in parentheses (kcal moP ) of the low-energy isomers of PtMCH2 (M = Cu, Ag, An, Pt, Rh)...

Figure 3.3a Low-energy isomers of Na clusters. Reprinted with permission from [123]. Copyright 1991 American Institute of Physics...

Figure 3.5(b) illustrates the radial part 0/o(r) of the dominant components of the occupied wave functions for the MN Naio in one of the low-energy isomers of Figure 3.3(b). The ordering is Is, Ip, Id, 2s, as expected, but the value of El=i although relatively small, is not zero (El = 0.056), thus indicating the necessity of higher harmonics for the description of the electron states. Hybridization, on the other hand, is mainly of the s-d... 

Figure 3.15 Atomic and magnetic structure of low-energy isomers of Fea and Fes computed within DFT-LSD-GGA. Configuration (c) is the ground-state structure for Fes. All the others are excited magnetic states. Reprinted from [27]...

Figure 3.17 Nb clusters low-energy isomers, reprinted from [223]. They have been described as two different cappings of the octahedron for Nbg, a bicapped pentagonal bipyramid (left) and a tricapped octahedron (right) for Nb9, and a bicapped antiprism for Nbio...

Figure 3.19 Na Mg low-energy isomers (a) for n = 6-9 and (b) for n = S. In (a) the two isomers correspond to the pentagonal (left) and the tetrahedral (right) growth paths. Reprinted from [237], with kind permission from Elsevier Science-NL, Sara Burgerhartstraat 25, 1055 KV Amsterdam, The Netherlands...

Xu, L., Cai, W S., Shao, X. G. (2006). Prediction of low-energy isomers of large fullerenes from C132 to Ci6o- Journal of Physical Chemistry A, 110(29), 9247-9253. 

Fig. 17 The ground state structures and some metastable low-energy isomers of (TiOz)n (n = l-6) clusters he point group symmet the relative enei ies (Af) with regard to the ground states are given in the parenthesis. Reproduced with permission from ref. 172. Copyright (2012) Wiley-VCH Verlag GmbH Co. KGaA, Weinheim.

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