Dimer ground-state

Fitting results for fs DFWM experiments of the formic acid dimer (ground state) rotational constants, CD constants, parametrized polarizability parameter cp, Ray s asymmetry parameter k and temperature T. ... 

Auzinsh, M.P. (1990). Nonlinear phase resonance of quantum beats in the dimer ground state, Opt. Spectrosc. (USSR), 68, 750-752. 

It follows from Eq. (42) that the ground state has ultrashort-range correlations with rc 1. For example, rc(y = 0) = 2 log-13, which coincides with the correlation length of the AKLT model. But at y = all correlations are zero except (S2i S2i+i) = — It implies that at y = the model (46-48) has a dimer ground state. 

Summary and Conclusions on Iron-series Dimers. In spite of reservations about the local spin density functional, calculations based on this approach yield much interesting information about these dimers. In particular, the spin energy is such a dominating influence that dimer ground states tend to have a net spin only one less than the separated atoms. Calculated binding energies agree with experi-... 

An EPR signal attributable to the spin-polarized triplet state of P-680 ( P-680) formed by recombination of P-680 Pheo was detected by illuminating PS II preparations at liquid helium temperature [141], The zero-field splitting parameters are identical to those of triplets of monomeric Chi in vitro. The triplet minus singlet spectrum of P-680 measured by absorption-detected magnetic resonance indicated a monomeric triplet but a dimeric ground state [166]. 

Since RSA s for arbitrary wavelengths are not known, it is important to be able to design molecules which behave as a RSA at a desired wavelength. Briefly, the idea is to use a dimer molecule formed from monomers whose ground state absorption peaks near the wavelength of interest. If synthesis of the dimer with fixed orientation of the monomers at desired distances from one another is possible, and the dimer is sufficiently stable to withstand dissociation upon absorption of two quanta of radiation, and a number of other criteria are satisfied, the dimer may behave as a RSA at the desired wavelength. The dimer ground state absorption is to a state in which the excitation is spread over both monomeric units and the dimer excited state absorption commences from this state to the doubly excited electronic state in which both monomeric units are excited. 

Consider a dimer molecule synthesized with the monomers tied together so that their relative geometry is fixed. The shift of the dimer ground state absorption spectrum relative to that of the monomer is due mainly to (a) the splitting of the first excited state of the dimer resulting from the dipole-dipole interaction... 

The sign of the shift of the dimer ground state absorption spectrum relative to the monomer is controlled by the positioning of the orientation of the monomers within the dimer. The first excited dimer states undergo first-order interaction to give... 

We start with the alternating Huckel chain in Eq. (1), which simply consists of the bond order operators pd,s for nearest-neighbor hopping between sites 2n, 2n -1 and 2n, 2n + 1. Following SSH [10,11] and LHS [8], we discuss the dimerized ground state and write the linear e-ph Hamiltonian, Eq. (11), in terms of the symmetry coordinates in Eq. (16) for single- and double-bond stretches. In the = 0 subspace, we have... 

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