Salmon and trout

Harris, William C.; Sage, Dean; Smith, Hugh M.; Townsend, C. H. T.

doi:10.5962/bhl.title.25500

Cited by 53 publications

(111 citation statements)

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“…where the inverse matrices are [ q r f so]-' = [ w 2 -Iz2 + ( 2 / h ) w 1 / 2 v ( q z f so)w"2]-1 (5) and in which w,, an element of w, is an unperturbed transition frequency and Y is the eigenvector matrix for the dispersion matrix in Eq. V( qz f so) is also real symmetric.…”

Section: Tdh Theorymentioning

confidence: 99%

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On the CD helix band for long helical polymers

Rabenold

Rhodes

1987

Biopolymers

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SynopsisThe CD helix bands for infinitely long helical polymers are shown to be composed of two parts: a derivative-shaped band plus an ordinary Gaussian-like band. The derivative-shaped band results from the zero-order term of an expansion while the Gaussian-like band results from the first-order expansion term. However, the intensities of the two bands are shown to be of the same order of magnitude. They are both linear in the coulombic coupling of transition charge densities for polymer transitions. The sum yields a skewed derivative-shaped band. The shapes of net CD helix bands are shown to not depend on the approximations used for averaging over orientations if the usual systems, such as polypeptides and polynucleotides, are considered in their long-wavelength spectral regions.

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Section: Tdh Theorymentioning

confidence: 99%

“…6 Loxsom's normal mode equati~n,'~ after it is symmetrized, has the same form as ours in Eq. (5). Ando17 and Deutsche20 both explicitly consider only the lowest monomer excitation and thus could not observe the skewing.…”

Section: This Contribution To the CD Ismentioning

confidence: 99%

On the CD helix band for long helical polymers

Rabenold

Rhodes

1987

Biopolymers

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“…[5][6][7][8][9] Ultrafast timeresolved experiments are now allowing the dynamics of bond breaking, impulsive system-solvent interaction, recombination, and subsequent vibrational relaxation to be observed in real time. 6,[10][11][12][13][14][15][16][17][18][19][20][21] Theory and simulation play an important role in clarifying the physical processes underlying the time-resolved measurements, and considerable insight has resulted from molecular dynamics simulations of photodissociation and subsequent relaxation to equilibrium. 5,6,[21][22][23][24][25][26][27][28] Photodissociation studies have also been extended to clusters, [29][30][31][32][33][34][35][36][37][38][39][40][41][42] which provide finite but many-body analogs of true condensed phases that are often more amenable to detailed analysis.…”

Section: Introductionmentioning

confidence: 99%

“…They thus represent a novel form of shock phenomena which exhibit nanoscale localization; such excitations can, in principle, be created and studied by recently developed condensed phase ultrafast spectroscopic techniques. [10][11][12][13][14][15][16][17][18][19][20][21]71,72 The organization of this paper is as follows: In Sec. II, we present our two-dimensional model of an I 2 impurity embedded in an Ar lattice.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale shock wave generation by photodissociation of impurities in solids: A molecular dynamics study

Borrmann

Martens

1995

The Journal of Chemical Physics

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The dynamics of shock wave generation, propagation, and decay in an Ar lattice following photodissociation of an I 2 impurity are studied using molecular dynamics simulation. A two-dimensional model is treated to allow the modeling of shock wave propagation over larger distances than easily accessible in full three-dimensional calculations. The shock waves are created on atomic length scales by binary collisions between the nascent photofragments and adjacent lattice atoms, and propagate long distances through the crystal in a highly directed, quasi-one-dimensional manner. As a consequence of the I/Ar mass ratio, the I fragments undergo multiple collisions with the adjacent Ar atoms situated along the I-I bond axis, generating pulse trains of shock waves, each with a characteristic initial energy, velocity, and decay rate. The dynamics of the system are interpreted using a simple one-dimensional hard sphere model.

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“…Experiments in other simple solvents show similar results and will be discussed in detail in a forthcoming publication. 8 The induced absorptions from 635-1000 nm have a slowly decaying component with a 2700-ps time constant, independent of wavelength. This is consistent with Kelley's observations and his assignment as an absorption from molecules trapped in (A,A') states.…”

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confidence: 99%

Rapid solvent-induced recombination and slow energy relaxation in a simple chemical reaction: Picosecond studies of iodine photodissociation inCCl4

Berg

Harris

1985

Phys. Rev. Lett.

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The time scale for solvent "caging" in the classic I 2 photodissociation reaction appears to be ^15 ps, on the basis of examination of new picosecond absorption spectra. The previously observed slow recovery ( > 100 ps) of molecular absorption is shown to be due to both ground-state vibrational relaxation and excited-state trapping in the recombined molecule. In addition, newly observed absorptions in the 350-400-nm region provide direct information on solvent-induced predissociation and excited-state vibrational relaxation.PACS numbers: 82.20. Rp, 61.20.Lc, 82.40Js, 82.50.Et A central problem in liquid-phase chemical dynamics is determination of the time scale of reaction for species trapped together in a solvent "cage." The iodine photodissociation reaction has been the primary model system for studying cage recombination, 1 yet the cage recombination time for this system is still in controversy. Some experiments have indicated an ~~100-ps recombination time, 2 ' 3 in disagreement with other experiments, 4 and in contrast with theoretical predictions 5 of 1-10-ps recombination times. This Letter reports results which strongly suggest that cage recombination occurs in ^15 ps. The results also demonstrate that both solvent-induced vibrational relaxation and excited electronic-state relaxation are important in the understanding of this reaction.The basic processes in iodine photodissociation which are needed to explain these results can be outlined with reference to the potential-energy diagram (Fig. 1). The reaction is initiated by a transition from the ground (X) state to a vibrational^ excited level of the bound B state. The solvent induces both vibrational relaxation within the B state, as well as crossing to several repulsive states (only one shown). After initial separation, the two atoms may escape through the solvent to dissociate permanently, or they may recombine on either the A, A', or X potential. Those recombining on the X potential must dissipate their excess vibrational energy to the solvent before they return to the initial state. Those recombining on the A or A' potentials must undergo a solvent-induced crossing to the X potential before they can vibrational^ relax to the initial state.Chuang, Hoffman, and Eisenthal 2 first probed the loss of absorption near the peak of the ground-state molecular absorption (530 nm) upon photodissociation. The bleach of the ground-state absorption showed a recovery time of -140 ps in CC1 4 , which was associated with atomic recombination. Nesbitt and Hynes, 6 however, presented a contrasting interpretation. The Franck-Condon principle predicts that the maximum absorption for a molecule in a given vibrational state will occur at an energy corresponding to a vertical transition from the classical turning points. For the X -* B transition, this implies that the absorption from a vibrationally relaxing X-state population will initially be in the near ir and will move to shorter wavelengths as the population relaxes (Fig. 1). Thus, only recombining X-state molecules...

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Salmon and trout

Cited by 53 publications

References 0 publications

On the CD helix band for long helical polymers

On the CD helix band for long helical polymers

Nanoscale shock wave generation by photodissociation of impurities in solids: A molecular dynamics study

Rapid solvent-induced recombination and slow energy relaxation in a simple chemical reaction: Picosecond studies of iodine photodissociation inCCl4

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