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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 39 for “"Molecular crystals"”.
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Modelling the morphology of molecular crystals
… good agreement with the test case of benzamide crystals grown with benzoic acid as an additive. The additive approach also allowed the effects of toluene solvent on the crystal habit of benzophenone to be considered By treating toluene as a tailor made additive it was possible from calculations …
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A theoretical study of molecular crystals
… method (BIM), has been proposed for molecular clusters and molecular crystals. An infinitely extended, periodic, one-dimensional zigzag hydrogen fluoride chain was studied with this method and the energies, structures, harmonic, and anharmonic frequencies of the infrared- and/or …
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Energy transfer and localization in molecular crystals
… condensed-phase energetic materials via reactive molecular dynamics (MD) simulations. We characterize the response of three unique high energy density molecular crystals to different means of energy input: electric fields of various frequencies (100 − 4000<em>cm</em>−1) and strengths, and direct …
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Dynamics of (ionic) molecular crystals and adsorbed layers
Contains fulltext : mmubn000001_136176534.pdf (Publisher’s version ) (Open Access)
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Vibrational Relaxation and Vibrational Cooling in Molecular Crystals
… and theoretically in low temperature crystals of complex molecules, specifically benzene, naphthalene, anthracene and durene. In addition to ps CARS data previously obtained on these pure crystals, the VR of dilute impurity molecules (naphthalene, anthracene) in crystalline host …
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Femtosecond time-resolved spectroscopy of organic molecular crystals
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1988.
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Electroabsorption spectroscopy of quasi-one-dimensional organic molecular crystals
… spectroscopy on quasi-one-dimensional organic molecular crystals such as PTCDA and MePTCDI vapor deposited thin films to clarify the involvement of the charge-transfer exciton in the lowest excited state. By a self-built experimental setup, two kinds of electroabsorption measurements, called …
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Ultrafast Dynamics in Quasi-One-Dimensional Organic Molecular Crystals
Der erste Teil der Arbeit beschäftigt sich mit ultraschnellen Relaxationsprozessen in quasi-eindimensionalen organischen Molekülkristallen. Als Modellsystem wird das Perylenderivat MePTCDI untersucht. Mit verschiedenen Methoden der optischen Ultrakurzzeit-Spektroskopie werden Prozesse der …
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Evaluation of Thermal Effects and Lattice Vibrations in Molecular Crystals
… be observed macroscopically, they are often of molecular origin, and determining why these effects occur can provide insight into the nature of chemical systems as a whole. A large portion of this work is dedicated to analyzing polymorphic forms and small organic molecules with interesting …
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Vibrational Relaxation and Delocalization in Molecular Crystals and Biological Systems
… of vibrational dynamics of hydrogen bonded molecular crystals.
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Evaluation of Non-Covalent Interaction Models in Molecular Crystals Using Terahertz Spectroscopy
… THz spectroscopy is sensitive to both the intermolecular and intramolecular forces that govern the formation of crystalline materials, it is an ideal tool to investigate the accuracy of calculated DFT crystal structures and their vibrational spectra. When using solid-state DFT, non-covalent …
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Pharmaceuticals on the Nanoscale: Multi-dimensional Electron Diffraction of Organic Molecular Crystals
… industry, an understanding of both the molecular structure and the microstructure of potential assets holds the key to controlling their physical and chemical properties. In turn, this may influence how a drug is manufactured or the dosage form via which it is delivered. To characterise …
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Computational Methodologies for the Simulation and Analysis of Low-frequency Vibrations in Molecular Crystals
… to calculate a host of physical phenomena in molecular solids ranging from mechanical elasticity to the energetic stability ordering of polymorphs. However, with the many software packages and methodologies available, it can be difficult to select the most suitable model for the problem at …
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Vibrational Dynamics in Disordered Molecular Crystals by Picosecond Coherent Raman and Photon Echo Spectroscopies (Exciton, Low Temperature)
… in isotopically and chemically disordered crystals at low temperature by picosecond time-delayed Coherent Anti-Stokes Raman Scattering (psCARS) and photon echo spectroscopy (PE).
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Towards routine modelling of condensed phases with the accuracy of quantum Diffusion Monte Carlo
Molecular crystals are critical in diverse fields, including organic semiconductors, optoelectronics, medicine, and pharmaceuticals. A primary aim of computational studies in this area is to aid experimental structure determination and predict finite-temperature relative stabilities with …
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Sonocrystallization and sonofragmentation
… i.e., sonocrystallization, or break existing crystals, i.e., sonofragmentation in solid-liquid mixtures. The sonofragmentation of ionic and molecular crystals is discussed in Chapters 2 and 3. When ultrasound was applied to slurries of ionic or molecular crystals, crystal breakage occurred not …
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Charge Transport in Organic Electronic Devices: From Nano to Macro-Scale
… through single molecules or two-dimensional molecular ensembles, to tens of micrometers in devices focusing on thin films or molecular crystals. The work outlined in this thesis examines the characteristics of electronic devices at both extremes by incorporating organic molecules in molecular …
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Investigating the molecular origin of polymorphism and transition pathways in organic semiconductors with bulky side chains
… to adopt multiple crystalline packing states. In molecular crystals, where the dominant interactions are van der Waals and weak quadrupole interactions, polymorphism is prevalent. In context of organic electronics, polymorphism offers a new avenue for enhancing device performance as slight changes …
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Dynamics of Phonons in Crystals as Studied by Picosecond Coherent Anti-Stokes Raman Spectroscopy
… dynamics of the motions of ions and molecules in crystals are of fundamental interest, but due to the short correlation times of the motions (generally in the picosecond or subpicosecond range) the study of the dynamics is a difficult experimental problem. At the same time, theoretical progress in …
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Quantum dynamics in condensed phases : charge carrier mobility, decoherence, and excitation energy transfer
… we study charge-carrier mobilities in organic molecular crystals, and develop a microscopic theory that describes both the coherent band-like and incoherent hopping transport observed in organic crystals. We investigate the structures of polaron states using a variational scheme, and calculate …
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