Molecular Motion in Crystalline Naphthalene:  Analysis of Multi-Temperature X-Ray and Neutron Diffraction Data

Abstract

Single crystals of h8-naphthalene have been examined by both X-ray and neutron diffraction over a range of temperatures from 5 to 295 K. The aim of this case study was to measure the anisotropic displacement parameters (ADPs) of carbons and hydrogens and to interpret them using the model of thermal motion proposed by Bürgi and Capelli (Acta Cryst. 2000, A56, 403). The traditional rigid-body analysis expresses the low-frequency motions in terms of molecular translations and librations only, whereas the Bürgi-Capelli treatment also includes the high-frequency internal modes. We show that a considerable improvement occurs by representing the internal modes by a single second-rank tensor and that a further improvement follows by including a Grüneisen parameter to account for volume thermal expansion. By applying the treatment to multi-temperature diffraction data, there is a considerable reduction in the ratio of number of adjustable parameters/number of independent observations.

Structural and excited-state properties of oligoacene crystals from first principles

“…For consistency, we use room-temperature experimental data for all acenes [93][94][95][96][97] except for hexacene, where crystallographic data are only available at T = 123 K [98]. For pentacene, we consider the thin-film polymorph (denoted below as P 3 ) because it is the one most commonly measured in experiment (see Sec.…”

“…These are compared to low-temperature experimental data, for T 16 K from Refs. [95,104,105] and extrapolated to 0 K as indicated in Appendix A (in black filled circles). For two pentacene polymorphs and hexacene, only experimental data at T 90 K is available [94,97,98] (in dark gray stars).…”

“…We begin our MBPT analysis of the acene series by intentionally using the experimental geometries [93][94][95][96][97][98] as our starting point. This is done to isolate errors associated with the particular flavor of the GW -BSE method used here from errors related to structural deviations (the latter are analyzed in Sec.…”

Computational methodology for solubility prediction: Application to the sparingly soluble solutes

“…Fortunately, according to X-ray data, naphthalene remains as a single polymorph at room temperature for pressures up to at least 0.5 GPa. 79,80 Raman studies also indicate that naphthalene undergoes no structural phase transition 81 at least up to 3.5 GPa and 450 K. We used the ambient naphthalene crystal structure 82 In the extended Einstein crystal method, we tether a number of atoms (either real or virtual) in each molecule, to restrain the molecular position and orientation. As described in Appendix B, within each molecule, these particles can be categorized into two groups, (1) a single "Central Atom" and (2) a small number of "Orientational Atoms."…”

First-Principles-Based Dispersion Augmented Density Functional Theory: From Molecules to Crystals

“…S8 Equilibrium volumes of benzene, naphthalene, and anthracene crystals calculated using the pure PBE and the PBE-lg methods. The pressures were calculated at the corrected experimental volumes at 0 K. C 10 H 8 neutron (Capelli et al 2006) C 10 H 8 x-ray (Oddershede et al 2004) C 10 H 8 x-ray (Brock et al 1982) C 10 H 8 x-ray (Cruickshank 1957) C 10 H 8 x-ray (Chanh et al 1972) C 10 H 8 x-ray (Pomomarev et al 1976) C 10 D 8 neutron (Baharie et al 1982) parabolic fit of Baharie's data a naphthalene P2 1 /a S10 Lattice parameters and volume of naphthalene crystal (P2 1 /a) as functions of temperature. The solid lines are parabolic fits to Baharie's neutron measurement on perdeuturated naphthalene (C 10 D 8 ) S10-1 .…”