Temperature- and pressure-dependent luminescence spectroscopy on the trans-[ReO2(pyridine)4]+ complex — Analysis of vibronic structure, luminescence energies, and bonding characteristics

2004 ◽  
Vol 82 (6) ◽  
pp. 1083-1091 ◽  
Author(s):  
John K Grey ◽  
Ian S Butler ◽  
Christian Reber
Keyword(s):  
Molecular Structure ◽  
Low Temperature ◽  
Room Temperature ◽  
Complex Analysis ◽  
Variable Pressure ◽  
Luminescence Spectroscopy ◽  
Luminescence Spectra ◽  
Vibronic Structure ◽  
Temperature Spectra ◽  
Temperature And Pressure

Resolved vibronic structure in electronic spectra provides a detailed view into how molecular structure changes after absorption or emission of a photon. We report temperature- and pressure-dependent luminescence spectra of trans-[ReO2(pyridine)4]I. Low-temperature spectra reveal long vibronic progressions in the totally symmetric O=Re=O (907 cm–1) and Re-pyridine (211 cm–1) stretching modes, indicating large structural displacements along these normal coordinates. The luminescence band maximum is at ca. 15 500 cm–1. Room-temperature spectra are somewhat less-resolved; however, intervals closely matching the O=Re=O frequency (~870 cm–1) persist at higher temperatures. The variable pressure spectra exhibit distinct changes in the vibronic patterns, and luminescence energies decrease by 16 ± 2 cm–1/kbar (1 bar = 100 kPa). Low-temperature spectra are modeled using two-dimensional potential energy surfaces to represent the initial and final electronic states, from which the quantitative normal coordinate offsets can be determined. We then adapt this model to the room-temperature, pressure-dependent data where it is possible to determine how the offsets and other important spectroscopic parameters vary with the pressure-induced changes of the molecular structure. Key words: trans-[ReO2(pyridine)4]I, low-temperature luminescence spectroscopy, high-pressure luminescence spectroscopy, vibronic structure, emitting state distortions.

Emitting-state properties of square-planar dithiocarbamate complexes of palladium(II) and platinum(II) probed by pressure-dependent luminescence spectroscopy

2009 ◽  
Vol 87 (11) ◽  
pp. 1625-1635 ◽  
Author(s):  
Caroline Genre ◽  
Geneviève Levasseur-Thériault ◽  
Christian Reber
Keyword(s):  
Crystal Structure ◽  
Luminescence Band ◽  
Room Temperature ◽  
External Pressure ◽  
Luminescence Spectroscopy ◽  
Luminescence Spectra ◽  
Square Planar ◽  
Temperature And Pressure ◽  
Monodentate Ligands ◽  
Crystalline Complexes Of

Temperature- and pressure-dependent Raman and luminescence spectra of four crystalline complexes of palladium(II) and platinum(II) with chelating diethyldithiocarbamate (EDTC) and pyrrolidine-N-dithiocarbamate (PDTC) ligands are reported. The crystal structure of [Pd(PDTC)2] was resolved at 120 K. Luminescence band maxima are observed at approximately 14 500 cm–1 and 16 000 cm–1 for the palladium(II) and platinum(II) complexes, respectively. Pressure leads to blue shifts of the band maxima by +9 and +13 cm–1/kbar for [Pd(EDTC)2] and [Pd(PDTC)2], and +15 cm–1/kbar for [Pt(EDTC)2]. These spin-forbidden d–d luminescence transitions have lifetimes of approximately 600 µs at temperatures below 20 K. Luminescence intensities at room temperature are low, but they increase significantly with external pressure. The experimental results show that strong increases of luminescence intensities caused by pressure are not limited to complexes with monodentate ligands, a result providing insight on the coordinates with emitting-state distortions responsible for this effect.

Organic Solvent Fumigation Bonding for Multi-Layer Poly(methyl Methacrylate) Microfluidic Device

2014 ◽  
Vol 609-610 ◽  
pp. 654-659 ◽  
Author(s):  
He Zhang ◽  
Xiao Wei Liu ◽  
Li Tian ◽  
Xiao Wei Han ◽  
Yao Liu
Keyword(s):  
Low Temperature ◽  
Organic Solvent ◽  
Methyl Methacrylate ◽  
Room Temperature ◽  
Microfluidic Devices ◽  
Saturated Steam ◽  
Silicone Adhesive ◽  
Cover Sheet ◽  
Temperature And Pressure ◽  
Bonding Method

In this paper, a novel bonding method for microfluidic devices was presented. The organic solvent fumigation bonding method can be used to produce multi-layer PMMA microfluidic devices under the condition of room temperature and low pressure. During the bonding, we choose chloroform as bonding solvents, the polyimide tape was used to protect no-need-bonding side of the cover sheet and the sealant silicone adhesive was used to protect the microstructure in the bonding side. The substrate was fumigated for 5minutes in the saturated steam conditions, then remove the polyimide tape as well as the sealant silicone adhesive. Assemble the fumigation cover sheet to the substrate with microchannel by using fixtures, soon after put the fixture and the substrates into the oven, dried at 50 °C for 10 minutes. Finally, remove the fixture, the bonding complete. Because of the bonding was accomplished under conditions of low temperature and pressure, the deformation of microchannel is very small. When the method was used for multilayer chip bonding, it also achieved good results.

Selective Luminescence Spectroscopy of Poly(p-Phenylene) Thin Films at Room Temperature

1995 ◽  
Vol 413 ◽  
Author(s):  
M. A. Drobizhev ◽  
M. N. Sapozhnikov ◽  
V. M. KobryanskII
Keyword(s):  
Thin Films ◽  
Luminescence Spectrum ◽  
Room Temperature ◽  
Selective Excitation ◽  
Luminescence Spectroscopy ◽  
Luminescence Spectra ◽  
Model Calculations ◽  
Localization Threshold ◽  
Low Energy Tail ◽  
Room Temperature Luminescence

ABSTRACTSelectively excited room-temperature luminescence spectra are reported for thin films of poly(p-phenylene) (PPP) deposited onto quartz substrata. The spectra exhibit a localization threshold in the low-energy tail of the luminescence excitation band at vloc.= 22400 cm−1, 2200 cm−1 below the maximum of the excitation spectrum. Upon laser excitation at Vex < Vloc., the maximum Vem of the luminescence spectrum shifts linearly with Vex due to selective excitation of polymer segments. It was found that there exists the frequency range where the slope of the Vem vs Vex dependence is smaller than unity, which corresponds to our previous model calculations for the case of selective excitation of chromophores through broad phonon bands. At vex > vloc,, the luminescence spectrum is independent of Vex. This behavior can be explained if one assumes that upon excitation below the localization threshold the luminescence is related to polymer segments directly excited by laser, whereas upon exciting above the threshold the fast energy relaxation takes place from initially excited states to lower-lying states, from which uminescence occurs.

Evaluation of Fourier Transform Near-Infrared for the Simultaneous Analysis of Light Alkene Mixtures

1997 ◽  
Vol 51 (9) ◽  
pp. 1303-1310 ◽  
Author(s):  
E. D. Yalvac ◽  
M. B. Seasholtz ◽  
S. R. Crouch
Keyword(s):  
Molecular Structure ◽  
Fourier Transform ◽  
Room Temperature ◽  
Near Infrared ◽  
Fiber Optic ◽  
Liquid Mixtures ◽  
Sample Cell ◽  
Light Alkenes ◽  
Temperature And Pressure

A Fourier transform near-infrared (FT-NIR) spectrometer incorporating a fiber-optic-coupled sample cell was used for simultaneous determination of ethylene and monoalkylated light alkenes in liquid mixtures at room temperature and pressure. Ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 1-decene were selected for the evaluation. Several additional alkylated alkenes (e.g., 1,1 dialkylated, cis, trans dialkylated, and trialkylated alkenes) were investigated to determine the effects of the molecular structure on this determination. The first overtone of the asymmetric =CH2 stretch of the monoalkylated alkenes was found to be unique for the light alkenes in the NIR region. This region of the spectrum was used for quantitative analysis using classical least-squares (CLS) regression. Ethylene/1-octene mixtures were studied as an example. The concentrations of these alkenes were determined with an error of less than 1% by weight.

Low-temperature Raman and Fourier transform infrared spectra of dodecacarbonyldirhenium(0), Re2(CO)10

1985 ◽  
Vol 63 (7) ◽  
pp. 1510-1517 ◽  
Author(s):  
Pierre D. Harvey ◽  
Ian S. Butler
Keyword(s):  
Fourier Transform ◽  
Low Temperature ◽  
Room Temperature ◽  
Metal Carbonyl ◽  
Carbonyl Complex ◽  
X Ray ◽  
Temperature Spectra ◽  
Ft Ir ◽  
Ir Study ◽  
First Time

The Raman spectrum of microcrystalline dodecacarbonyldirhenium(0), Re2(CO)10, has been reinvestigated at 67 K using one of the latest fully-computerized spectrometers available. Previously unobserved peaks have been detected mainly in the 13CO-satellite (2150–1900 cm−1), and overtone and combination regions (1300–700 and 4300–3800 cm−1). This is the first time that Raman-active first CO overtones and combinations of a metal carbonyl complex have been reported. They were earlier thought to be too weak to be detected. Assignments are proposed for the majority of these new peaks together with those from a similar low-temperature (~70 K) FT-ir study. In general, the D4d selection rules are obeyed, but the activity of some forbidden bands reveals that the molecule is slightly distorted in the solid state in agreement with its X-ray structure. The similarity of the low-temperature spectra to those obtained at room temperature indicates that no phase change occurs throughout the temperature range investigated.

Spectra in the O-H stretching region of mono- and oligo-saccharides at low temperatures

1968 ◽  
Vol 21 (5) ◽  
pp. 1257 ◽  
Author(s):  
AJ Michell
Keyword(s):  
Fine Structure ◽  
Low Temperature ◽  
Low Temperatures ◽  
Room Temperature ◽  
Coupled Vibrations ◽  
Temperature Spectra

Spectra in the O-H stretching region of some mono- and oligosaccharides have been obtained at low temperatures. Bands in the low-temperature spectra were found to be sharper and better resolved, and some bands were revealed which were not apparent at room temperature. Spectra have also been obtained in both the O-H and O-D stretching regions of partly deuterated samples of two glycosides and an oligosaccharide. From these it has been shown that the fine structure in the O-H stretching region of the spectra of these compounds arises from coupled vibrations rather than from separate vibrations of individual groups. This coupling is probably the underlying reason for the large widths of bands in this region of the spectrum of carbohydrates.

ESEM - A multipurpose surface Electron Microscope

1986 ◽  
Vol 44 ◽  
pp. 632-633 ◽  
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Environmental Scanning ◽  
Gas Composition ◽  
Saturated Water Vapor ◽  
Surface Electron ◽  
Current State ◽  
Saturated Water ◽  
New Type ◽  
Temperature And Pressure

Over recent years a new type of electron microscope - the environmental scanning electron microscope (ESEM) - has been developed for the examination of specimen surfaces in the presence of gases. A detailed series of reports on the system has appeared elsewhere. A review summary of the current state and potential of the system is presented here.The gas composition, temperature and pressure can be varied in the specimen chamber of the ESEM. With air, the pressure can be up to one atmosphere (about 1000 mbar). Environments with fully saturated water vapor only at room temperature (20-30 mbar) can be easily maintained whilst liquid water or other solutions, together with uncoated specimens, can be imaged routinely during various applications.

Survival of mouse blastocysts after low-temperature preservation under high pressure

2004 ◽  
Vol 52 (4) ◽  
pp. 479-487 ◽  
Author(s):  
Cs. Pribenszky ◽  
M. Molnár ◽  
S. Cseh ◽  
L. Solti
Keyword(s):  
Phase Transition ◽  
Hydrostatic Pressure ◽  
Low Temperature ◽  
High Hydrostatic Pressure ◽  
Room Temperature ◽  
Freezing Point ◽  
Significant Loss ◽  
Embryo Cryopreservation ◽  
Subzero Temperatures ◽  
Survival Capacity

Cryoinjuries are almost inevitable during the freezing of embryos. The present study examines the possibility of using high hydrostatic pressure to reduce substantially the freezing point of the embryo-holding solution, in order to preserve embryos at subzero temperatures, thus avoiding all the disadvantages of freezing. The pressure of 210 MPa lowers the phase transition temperature of water to -21°C. According to the results of this study, embryos can survive in high hydrostatic pressure environment at room temperature; the time embryos spend under pressure without significant loss in their survival could be lengthened by gradual decompression. Pressurisation at 0°C significantly reduced the survival capacity of the embryos; gradual decompression had no beneficial effect on survival at that stage. Based on the findings, the use of the phenomena is not applicable in this form, since pressure and low temperature together proved to be lethal to the embryos in these experiments. The application of hydrostatic pressure in embryo cryopreservation requires more detailed research, although the experience gained in this study can be applied usefully in different circumstances.

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