Interacting molecular motors: Efficiency and work fluctuations

Abstract

We investigate the model of "reversible ratchet" with interacting particles, introduced by us earlier [Europhys. Lett. 84, 50009 (2008)]. We further clarify the effect of efficiency enhancement due to interaction and show that it is of energetic origin, rather than a consequence of reduced fluctuations. We also show complicated structures emerging in the interaction and density dependence of the current and response function. The fluctuation properties of the work and input energy indicate in detail the far-from-equilibrium nature of the dynamics.

Structures, Stabilities, and Electronic and Optical Properties of C58Fullerene Isomers, Ions, and Metallofullerenes

“…[20] Upon harmonic vibrational analyses at B3LYP/6-31G(d) level, relative concentrations (mole fractions) X i of the ith isomer among m isomers in a wide range of temperatures can be evaluated by a compact formula (for details, see the Supporting Information). [21] The ZINDO method [22] in combination with the sum-over-states (SOS) model [23] is employed to calculate the second-order hyperpolarizabilities of C 58 fullerenes. The reliability of the ZINDO method has been checked for many systems, and it is reliable for fullerene studies.…”

Predicting stabilities of endohedral metallofullerenes Yb@C84

“…Although the described methodology is only approximate, it is quite appropriate for large molecules and its success is well documented (see, e. g., [38] and the references therein). Moreover, for evaluation of molar fractions we enjoy an approximate cancellation of various correction terms due to anharmonicity, finite basis-sets and other terms, thus increasing the reliability of the model [38]. The method has been applied extensively to fullerenes and endohedral metallofullerenes (see, e. g., [24,39,40] and references therein) and so far no experiments based on the electric-arc technique were found that could not be rationalized in this way.…”

Computations on three isomers of La@C74

“…Moreover, the SDD (Stuttgart/Dresden) basis set [35] was also employed (with the SDD effective core potential for La) for the single point calculations while for the carbon atoms the 6-31G* or 6-311G* basis set was used (denoted here by 6-31G * ∼sdd or 6-311G * ∼sdd -see Table I). The Gibbs energies were evaluated using the rotational-vibrational partition functions constructed [36] from the calculated structural and vibrational data using the rigid rotator and harmonic oscillator (RRHO) approximation. Although the temperature region where fullerene or metallofullerene electric-arc synthesis takes place is not yet known, the new observations [37] supply some arguments to expect it around or above 1,500 K. Thus, the computed results discussed here are also focused on the temperature region.…”

“…Relative concentrations (mole fractions) x i of m isomers can be evaluated [36] through their partition functions q i and the enthalpies at the absolute zero temperature or ground-state energies H o 0,i (i.e., the relative potential energies corrected for the vibrational zero-point energies) by a compact formula:…”

“…Equation (1) is an exact formula that can be directly derived [36] from the standard Gibbs energies of the isomers, supposing the conditions of the interisomeric thermodynamic equilibrium. The electronic partition function for Eq.…”