Heat capacity prediction for polynuclear aromatic solids using vibration spectra

Sallamie, Nasser; Shaw, John M.

doi:10.1016/j.fluid.2005.07.022

Cited by 25 publications

(28 citation statements)

References 56 publications

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“…Frequency spectra calculations were performed for the optimized structures using B3-LYP/6-311G. This computational approach is in good agreement with experimental spectra, Sallamie and Shaw [13], although the computed wave numbers are typically shifted to slightly higher values vis-à-vis experimental measurements. It should also be noted that this approach is computationally intensive.…”

Section: Computation Detailsmentioning

confidence: 52%

“…Sallamie and Shaw [13] reported a predictive technique employing a combined Debye-Einstein model for computations of heat capacities at constant pressure from 0 K to the temperature of fusion for solid polynuclear aromatic compounds. Average absolute errors of less than 0.03 JK −1 g −1 were obtained for eight compounds using:…”

Section: Computation Detailsmentioning

confidence: 99%

“…(1) represents a difference between heat capacity at constant pressure C p and C v (C v = Debye term + Einstein term) and was suggested by Pan et al [14] for correlation of C p values for linear macromolecules. For large molecules the difference between C p and C v is less than 5% of the C p value [13], even at the melting point, and this difference is often neglected for large molecules. We employ Eq.…”

Section: Computation Detailsmentioning

confidence: 99%

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A similarity variable for estimating the heat capacity of solid organic compounds

Laštovka

Sallamie

Shaw

2008

Fluid Phase Equilibria

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Section: Computation Detailsmentioning

confidence: 52%

Section: Computation Detailsmentioning

confidence: 99%

Section: Computation Detailsmentioning

confidence: 99%

See 1 more Smart Citation

A similarity variable for estimating the heat capacity of solid organic compounds

Laštovka

Sallamie

Shaw

2008

Fluid Phase Equilibria

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“…Consequently, we disregard this contribution (and any other from low-energy charge-carrying excitations 20 ). In solids states with three translational and three rotational degrees of freedom, the specific heat contribution from acoustic phonons can be calculated by the Debye model 21 :…”

Section: A Nonlinear Current-voltage Characteristicsmentioning

confidence: 99%

“…Due to the low dispersion of both internal and external modes, their contribution to the specific heat in molecular solids is reasonably well described by a series of harmonic oscillators 21 . To estimate the mean energy of the contributing optical phonon modes, we approximate our data by an effective Einstein…”

Section: A Nonlinear Current-voltage Characteristicsmentioning

confidence: 99%

Energy exchange between phononic and electronic subsystems governing the nonlinear conduction inDCNQI2Cu

et al. 2015

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We present a dynamical study on the nonlinear conduction behaviour in the commensurate charge-density-wave phase of the quasi-one-dimensional conductor DCNQI 2 Cu below 75 K. We can accurately simulate magnitude and time-dependence of the measured conductivity in response to large voltage pulses by accounting for the energy exchange between the phononic and electronic subsystems by means of an electrothermal model. Our simulations reveal a distinct non-equilibrium population of optical phonon states with an average energy of E ph = 19 meV being half the activation energy of about ∆E a = 39 meV observed in DC resistivity measurements. By inelastic scattering, this hot optical phonon bath generates additional charge-carrying excitations thus providing a multiplication effect while energy transferred to the acoustic phonons is dissipated out of the system via heat conduction. Therefore, in high electric fields a preferred interaction of chargecarrying excitations with optical phonons compared to acoustic phonon modes is considered to be responsible for the nonlinear conduction effects observed in DCNQI 2 Cu.

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Molecular Rotors of Coronene in Charge‐Transfer Solids

Yoshida

Shimizu

Yajima

et al. 2013

Chemistry A European J

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Ten types of neutral charge transfer (CT) complexes of coronene (electron donor; D) were obtained with various electron acceptors (A). In addition to the reported 7,7,8,8-tetracyanoquinodimethane (TCNQ) complex of 1:1 stoichiometry with a DA-type alternating π column, TCNQ also afforded a 3:1 complex, in which a face-to-face dimer of parallel coronenes (Cor-As) is sandwiched between TCNQs to construct a DDA-type alternating π column flanked by another coronene (Cor-B). Whereas solid-state (2)H NMR spectra of the 1:1 TCNQ complex formed with deuterated coronene confirmed the single in-plane 6-fold flipping motion of the coronenes, two unsynchronized motions were confirmed for the 3:1 TCNQ complex, which is consistent with a crystallographic study. Neutral [Ni(mnt)2] (mnt: maleonitriledithiolate) as an electron acceptor afforded a 5:2 complex with a DDA-type alternating π column flanked by another coronene, similar to the 3:1 TCNQ complex. The fact that the Cor-As in the [Ni(mnt)2] complex arrange in a non-parallel fashion must cause the fast in-plane rotation of Cor-A relative to that of Cor-B. This is in sharp contrast to the 3:1 TCNQ complex, in which the dimer of parallel Cor-As shows inter-column interactions with neighboring Cor-As. The solid-state (1)H NMR signal of the [Ni(mnt)2] complex suddenly broadens at temperatures below approximately 60 K, indicating that the in-plane rotation of the coronenes undergoes down to approximately 60 K; the rotational rate reaches the gigahertz regime at room temperature. Rotational barriers of these CT complexes, as estimated from variable-temperature spin-lattice relaxation time (T1) experiments, are significantly lower than that of pristine coronene. The investigated structure-property relationships indicate that the complexation not only facilitates the molecular rotation of coronenes but also provides a new solid-state rotor system that involves unsynchronized plural rotators.

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Heat capacity prediction for polynuclear aromatic solids using vibration spectra

Cited by 25 publications

References 56 publications

A similarity variable for estimating the heat capacity of solid organic compounds

A similarity variable for estimating the heat capacity of solid organic compounds

Energy exchange between phononic and electronic subsystems governing the nonlinear conduction inDCNQI2Cu

Molecular Rotors of Coronene in Charge‐Transfer Solids

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