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| Chemistry Department Facilities |
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| Research Instrumentation |
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| Labs are well supplied with the state-of-the-art equipment needed to carry out contemporary research projects successfully and conveniently. Major equipment for research includes six NMR spectrometers, three mass spectrometers, 11 lasers, a CCD X-ray diffractometer, as well as a large number of additional pieces of equipment. A very experienced staff maintains the equipment, makes modifications to implement new experimental techniques and trains graduate students on the use of the instruments. The equipment is available for all chemistry graduate students to use, offering them experience on a large array of modern research instrumentation. |
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| Molecular Spectroscopy Laboratory |
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| The Molecular Spectroscopy Laboratory has evolved over the past 12 years to become a regional resource for NMR instrumentation. The lab operates six superconducting NMR spectrometers including a Unityplus 750 MHz instrument with liquid state accessories to perform every possible experiment yet devised and an INOVA 400 MHz system. The techniques available on these instruments include quadruple resonance, shaped pulses for selective excitation, pulsed field gradient work, and 2D-, 3D- and 4D- experiments. The 750 MHz NMR also is equipped to perform a wide range of solid-state NMR experiments. The facility also has two 200 MHz spectrometers dedicated to solid state experiments; one is set up for routine 13C and 15N CPMAS experiments and the second is configured to perform a variety of specialized 1D-, 2D-, wideline and triple resonance experiments. Two 300 MHz instruments are dedicated to solution NMR work. One is used for routine service work and can provide 13C, 19F and spectra with all 1H, 31P, functions adjusted by computer, The second instrument is multinuclear and can be reserved for large blocks of time in order to perform long-term signal averaging and 2D-experiments. |
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| The Center for Laser and Optical Spectroscopy |
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Researchers within the Center for Laser and Optical Spectroscopy possess world-class laser facilities, including 11 tunable laser systems covering a wide range of frequencies and time resolutions. A wide variety of laser equipment is present in the Center, having pulse-widths ranging from the femtosecond to nanosecond time-scale, and tunability from the ultraviolet to the near infrared.
Ultrafast spectroscopy experiments are performed with a Quantronix regenetively amplified femtosecond laser system consisting of a Coherent Vitesse oscillator, a Nd:YLF DQE pump laser, Titan regenetively amplified/multipass laser, and three TOPAS optical parametric amplifiers. This laser system is used for transient absorption and fluorescence up-conversion experiments in the femtosecond regime. Condensed phase experiments measuring excited state lifetimes, energy and electron transfer, and one- and two-photon pump-probe absorption experiments are routinely performed using this laser system.
Experiments using on the picosecond time-scale are performed using a Quantronix mode-locked picosecond Nd:YLF laser that pumps a Coherent 700 dye laser and is capable of producing 1 ps pulses over a range of wavelengths. A variety of condensed and gas phase experiments are performed using this laser system, such as time-correlated single photon counting (TCSPC) experiments to measure fluorescence lifetimes and changes in fluorescence anisotropy that are useful for determining volume changes in dendrimers and polymers as a function of changing environment. When used in conjunction with a three-stage dye amplified laser, rotational coherence experiments are performed on gas phase molecules and molecular clusters.
Five nanosecond Nd:YAG and excimer pumped dye laser systems within the center offer tunability in the nanosecond time-scale from the near infrared to the ultraviolet. Typical condensed-phase experiments on the nanosecond time-scale include laser flash photolysis experiments on short-lived reactive intermediates and excited states. Two-color, two-photon experiments on highly reactive intermediates and excited states in solution also are performed with these laser systems. Several nanosecond laser systems are used to carry out various pump-probe experiments on jet-cooled gaseous molecules to study their excited-state dynamics.
The center has two single-frequency continuous-wave (less than a few megahertz bandwidth) ring lasers operating in the UV/Visible range. The ring laser is pulse-amplified by about a factor of 105 using a dye amplifier, to produce high-intensity light pulses with very narrow line widths. The pulse-amplified ring laser is combined with skimmed supersonic molecular beams of small Doppler widths to determine structures of van der Waals molecules. The structural information of the species also is probed by mass-resolved rotational coherence spectroscopy using the regeneratively amplified picosecond laser system and time-of-flight mass spectrometers. There are two single-frequency continuous-wave infrared laser systems that are used for high-resolution cavity-ringdown studies of molecular vibrations, torsions and rotations. These include a PPLN OPO and an external-cavity diode laser. Also available in the center is a FT-IR spectrometer that has a range in the mid-IR and near-IR, and has advanced features such as dual channel collection step-scan capabilities for polarization modulation (VCD, PMIRRAS) and time-resolved (20 ns) experiments.
Combined with several supersonic molecular beam apparati, the center has unique, state-of-the-art capabilities of probing elementary processes of importance in chemistry (i.e., electron-transfer, energy-transfer, energy dissipation, molecular motions, structural and chemical changes) that occur on a broad range of time scales.
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| Mass Spectrometry Center |
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The facility operates four research-grade mass spectrometers. The Micromass AutoSpec-Q mass spectrometer has hybrid EBEhQ geometry and is equipped with EI, CI and FAB ion sources as well as several collision cells; it allows for a large array of mass and tandem mass spectrometry (MS/MS) experiments for the analysis of unknown structures as well as the investigation of the reactions and dissociations mechanisms of gas-phase ions and reactive neutral intermediates. The Bruker Reflex-III MALDI-ToF mass spectrometer is ideally suitable for the analysis of synthetic polymers and biopolymers. Mass spectra can be acquired in linear or reflectron modes, which maximize the sensitivity and resolution, respectively. The Micromass Q-ToF Ultima mass spectrometer is a quadrupole-orthogonal-acceleration-ToF instrument with exceptional mass accuracy and resolution in both MS and MS/MS modes; the MS/MS capability is essential for structural characterizations, especially in sequence analyses. The Bruker Esquire-LC ion trap mass spectrometer enables LC/MS and multi-stage mass spectrometry studies. Analytes can be ionized by electrospray or atmospheric pressure chemical ionization, and the ions produced this way can be subjected to several stages of successive dissociation in order to determine their structures. The ion trap also is ideally suitable for fundamental studies in gas-phase ion chemistry.
All instruments are interfaced with powerful systems for data collection, summation and presentation, and contain software that facilitates the analysis of peptides, proteins and polymers. The MS Center specializes in the studies of novel and functional polymers and vigorously pursues the development of new approaches for the analysis of polymer sequences and architectures. |
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| The Molecular Structure Facility |
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| The facility has a state-of-the-art single crystal CCD X-ray diffractometer equipped with a low temperature (-150oC) device. The instrument is housed in a climate-controlled facility equipped with microscopes for crystal inspection and computer workstations for structure solution using the SHELXTL software package. Data can be rapidly acquired on small crystals (0.1mm), and frequently structures can be elucidated during hemisphere collection. |
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| Computer Facilities |
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The Department of Chemistry computers connect to the university's 10 gigabit backbone via switch 10/100/1000 connections. This combined with the university's Internet 2 connection provides high-speed access to Ohio's Super Computer facility and other computational resources through out the country.
The University offers wireless network connectivity across campus, enabling students with laptops to connect to the Internet or check e-mail without having to be physically connected. UA also has a site license agreement with Microsoft enabling students to acquire many of its products at minimal cost. |
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| Additional Resources |
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| Research is further supported by such specialized equipment as a Nicolet Nexus-870 Fourier transform IR (FTIR) system with capabilities to acquire time-resolved and 2-D data sets and the ability to perform vibrational circular dichroism and plasmon resonance spectrometry. Chromatographic equipment includes both gas chromatography (GC) and an ion-trap detector GC/MS system with autosampler and high-performance liquid-chromatography (HPLC) systems with UV/Vis, rapid-scanning UV-VIS, and refractive index detection capabilities for analytical and preparative scale separations. The Department of Chemistry also has a differential thermal analyzer, an electrochemical analyzer, photochemical and flow-photolysis reactors, and an atomic absorption spectrometer. |
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