Optical Spectroscopy
At DiSC, molecular, condensed phase materials and nanoscale systems and the phenomena due to their interaction with the electromagnetic radiation at frequencies from the infrared to the ultraviolet are actively investigated by a wide range of spectroscopic instrumentation and techniques. Qualitative and quantitative analyses are daily performed by these instruments, both for the research projects and for services to industry. The equipments presented in this section include both traditional spectrometers and advanced systems with tunable functions and investigation philosophy. They are grouped in the following categories:
Fourier Transform Infra Red Spectroscopy (FT-IR)
A remarkable number of FT-IR spectrometers operates at DiSC. Gas, liquid and solid samples can be measured. A wide range of attachments allows to decline the technique as Attenuated Total Reflectance (ATR), Diffuse Reflectance Infrared Fourier Transformed (DRIFT) and Polarization Modulation – Infrared Reflection Adsorption Spectroscopy (PM‐IRRAS). Some of the equipment are shown below:
Nicolet FT-IR Nexus
contacts: pierluigi.zanonato@unipd.it
location at DiSC: 215-00-056
Nicolet FT-IR (Thermo Optek)
This spectrophotometer is equipped with accessories for ATR measurements (Smart iTR). The sample compartment is confined in a controlled atmosphere box.
contacts: silvia.gross@unipd.it
location at DiSC: 215-01-069
Nicolet FT-IR Nexus
This FT-IR Nexus spectrometer is equipped with many types of different accessories and cells. KBr pellets are daily sintered to collect transmittance and absorbance spectra of solid dispersions. Samples dissolved in nearly any solvent can be measured by CaF2 cells for liquids, at optical path lengths of 0.05mm, 0.1mm, 1mm, 1 cm. Typical investigated solutions are water, deuterium oxide and chloro - aliphatic solutions. A low angle reflectance attachment allows to measure the reflectance of solid samples at 15° grazing angle, which is a geometrical configuration particularly suitable for the study of coatings. The reflectance of liquid samples can be measured in ATR (Attenuated Total Reflectance) by a multipass cell equipped with a Germanium crystal.
The highest spectral resolution is reached by mounting an MCT (Mercury Cadmium Telluride) detector with liquid nitrogen cooling of the sensor. The spectra can be further analysed by the SpectraCalc software, which has proved to be powerful in case of deep analysis tasks as absorbance peak deconvolution, spectra subtractions, derivative representations. A senior technician permanent staff manages the equipment, both for students training, research collaborations, commercial services to the industry or forensic requests.
contacts: renato.schiesari@unipd.it
location at DiSC: 215-03-071
Bruker TENSOR 27
contacts: cristina.tubaro@unipd.it
location at DiSC: 210-04-011
JASCO 4100
The JASCO 4100 FT-IR Spectrophotometer is equipped with the Diffuse Reflectance Spectroscopy attachment. Actually the system is dedicated to the students training.
contacts: nicola.tiso@unipd.it
location at DiSC: 210-04-020
Raman, Surface Enhanced Raman Spectroscopy (SERS), Non-Linear Spectroscopy (NLS) and other advanced laser spectroscopies
Thermo Scientific DXR MicroRaman
The available configuration and optics allow high-resolution depth profiling and characterization of surface areas with x-y area maps and x-z maps.
location at DiSC: 215-01-068
contacts: mauro.sambi@unipd.it
inVia Renishaw Raman and SERS
inVia Renishaw micro-Raman spectrometer with excitations at 488, 633 and 780 nm.
location at DiSC: 215-01-141
contacts: moreno.meneghetti@unipd.it
Raman/SERS and CW Z-Scan
The main excitation lines are 488, 514, 647 nm (Ar/Kr gas laser) and the range 700-900 nm (CW Titanium Sapphire laser). The signal collection is available in Micro and Macro configuration. Low frequency Raman modes can be measured, down to a few cm-1. The measurement of non-linear optical absorption coefficient and refractive index can be carried out, with the same laser sources as the Raman experiment.
location at DiSC: 215-01-122
contacts: raffaella.signorini@unipd.it
Non-linear Spectroscopy
Multi-photon absorptions from ground and excited states studied with nano-second pulses also using pump and probes measurements.
location at DiSC: 215-01-141
contacts: moreno.meneghetti@unipd.it
fs-microscopy, fluorescence lifetime imaging microscopy (FLIM) and fluorescence correlation spectroscopy (FCS)
This equipment includes a Ti:sapphire laser (Coherent-Mira900) emitting trains of pulses at 76 MHz repetition rate and having ca. 150 fs pulse duration and 1 W power. The emission wavelength can be tuned in the ranges 720-920 and 360-460 nm. The laser beam can be sent to an external optical set-up or coupled to a laser scanning confocal microscope (Olympus-BX51WX). This microscope is also equipped with a CW Argon laser emitting at 488 and 514 nm. The sample emission signal is detected by a photomultiplier tube or sent to an avalanche photodiode coupled to a fast electronics, for time-resolved emission analysis (Picoquant-PH300-Symphotime software).
An inverted microscope (Olympus-IX71) coupled to an Ar laser (Coherent-Innova) is implemented for total internal reflection microscope (TIRFM) analysis. This instrumentation is used for the measurement of two-photon absorption spectra, for one- and two-photon polymerization in photosensitive resins and for confocal imaging of fluorescent samples. The time-resolved fluorescence analysis can also be performed for sample having fluorescence lifetimes in the range 0,3-5ns. The system is also implemented for fluorescence lifetime imaging microscopy (FLIM) and fluorescence correlation spectroscopy (FCS).
location at DiSC: 215-01-124
contacts: camilla.ferrante@unipd.it ; raffaella.signorini@unipd.it
Amplified laser for time and frequency resolved multi-purposes spectroscopies
The optical bench is equipped with an amplified femtosecond laser system composed by an oscillator (Mai-Tai Spectra Physics) seeding a pulse amplifier (Empower+Spitfire Spectra Physics) delivering 150 fs long pulses at 800 nm with 1KHz repetition rate and 800 mW average power. The laser output can be used to pump an optical parametric amplifier (OPA800 Spectra Physics) delivering 150-200 fs pulses in the range 480-2000 nm . There is also a fully equipped optical set-up used for time and frequency resolved non-linear spectroscopy experiments.
The set-ups currently available allow measuring: i) transient absorption spectra in the range 450-750 nm, pumping the sample at 440 nm or in the range of the OPA800; ii) pump and probe experiments between 800 and 1200 nm; iii) Z-scan experiments to measure third order non-linear optical response in the range of OPA800 and at 800nm; iv) characterization of the stimulated emission and amplified stimulated emission of suitably doped thin films. The optical set up can be modified in any moment to provide in principle for many other time and frequency resolved optical spectroscopy experiments.
location at DiSC: 215-01-125
contacts: camilla.ferrante@unipd.it
2D laser ultra-fast coherent spectroscopy
The optical bench of this equipment includes an amplified Ti:sapphire laser (Coherent Libra) emitting trains of pulses at 3KHz repetition rate and having ca. 100 fs pulse duration, 2.5W power and central wavelength 800 nm. The output of the Libra is used to pump a noncollinear optical amplifier (NOPA, TOPAS white, Light Conversion). The final output of the NOPA is a train of pulses having a central wavelength tunable from 450 to 750 nm (plus second harmonic: 225-375 nm), time duration between 8 and 30 fs and energy of some mJ per pulse. These laser sources are employed for ultrafast time-resolved spectroscopy measures in particular pump-probe and 2D photon echo. Potentially any kind of ultrafast (multidimensional) coherent spectroscopy can be easily implemented. These techniques are employed to study ultrafast relaxation dynamics and energy transfer processes in the first picosecond after photoexcitation.
location at DiSC: 215-00-098
contacts: elisabetta.collini@unipd.it
Near-Infra-Red-Visible-Ultra-Violet (NIR-Vis-UV) Spectroscopy
NIR Spectroscopy
Agilent Cary 5000 (two of them)
The Near-Infrared Spectrophotometer VARIAN Cary 5000 is equipped with temperature control on the sample compartment. Measurements can be carried both on solution and solid samples (such as transparent plastics).
contacts: enzo.menna@unipd.it
location at DiSC: 170-03-006
Cary 5 E UV-Vis-NIR (two of them)
Cary 5E with interface-diffuse reflectance accessory Cary 4/5- extension samples; Comp’t 4/5 for the optical characterization of the solutions and of the nanocomposite systems either in the form of thin films or bulk materials.
contacts: silvia.gross@unipd.it
location at DiSC: 215-01-069
UV-Vis Spectroscopy
The UltraViolet-Visible (UV-Vis) Spectrophotometers housed at DiSC are widespread in the research and teaching laboratories. Some of them are reported below:
TECAN infinite M1000 PRO
The TECAN Infinite M1000 Pro allows for the simultaneous collection of absorption and emission spectra in the UV-Visible range on arrays of up to 300 samples, thanks to its interface to a microplate reader, hosted in a temperature controlled compartment.
contacts: leonard.prins@unipd.it
location at DiSC: 170-03-006
TECAN Infinite f200
The TECAN Infinite F200 is a spectrophotometer (UV/Vis and fluorescence) equipped with a microplate reader containing a thermostatted sample compartment. Only selected wavelengths for excitation/emission are available.
contacts: leonard.prins@unipd.it
location at DiSC: 170-03-006
VARIAN Cary 4000 equipped with Cary DUAL CELL PELTIER ACCESSORY
The UV-Vis VARIAN Cary 4000 spectrophotometer is equipped with a dual cell peltier accessory for the temperature control of the cuvette compartment.
contacts: pierluigi.zanonato@unipd.it
location at DiSC: 215-00-056
VARIAN Cary 100 Bio
contacts: cristina.tubaro@unipd.it
location at DiSC: 210-04-011
Agilent Cary 100
contacts: fabrizio.mancin@unipd.it
location at DiSC: 170-03-006
Agilent Cary 50
The Agilent Cary 50 UV-Vis spectrophotometer is equipped with a home-assembled temperature control of the sample compartment.
contacts: fabrizio.mancin@unipd.it
location at DiSC: 170-03-006
PerkinElmer LAMBDA 45
The Perkin Elmer LAMBDA 45 UV-Vis spectrophotometer is equipped with a home-assembled temperature control of the sample compartment.
contacts: fabrizio.mancin@unipd.it
location at DiSC: 170-03-006
VARIAN Cary 50 Probe
contacts: pierluigi.zanonato@unipd.it
location at DiSC: 215-00-052
Shimadzu 2501PC UV-Vis
The 2501PC UV-Vis spectrophotometer is equipped with two radiations sources, a deuterium and a tungsten lamp. The measurable wavelength ranges from 190 to 1100 nm, the spectral bandwidth emerging from the slit after the monochromator can be varied in the range from 0.1 to 5 nm. The instrument is actually useful for the protein purity and for the measurement of the concentration of protein solutions. A senior technical permanent staff manages students training, as well as research collaborations and services to industry.
contacts: renato.schiesari@unipd.it
location at DiSC: 215-03-073
Circular Dichroism
JASCO J715 Circular Dichroism spectropolarimeter
A JASCO J715 spectropolarimeter allows for the measurement of the circular dichroic spectra in the wavenumber range from 190 nm to 900 nm with temperature control of the sample compartment and programmable temperature ramps from ca. 20°C to 95°C. Spectral bandwidth can be varied from 0.1 to 10 nm. The sensitivity at 500 nm is 0.035 millidegrees. Radiation source comes from a Xenon lamp. The instrument is daily employed in the study of protein unfolding, chlorophyll pigments, natural and synthetic porphyrin systems. A permanent senior technical expert is daily managing the instrument timetable and provide students training, research collaborations, commercial services to industry.
contacts: renato.schiesari@unipd.it
location at DiSC: 215-03-071
Fluorimetry
Fluorimetry Facility at DiSC include:
FLS 1000 fluorimeter
The new FLS1000 by Edinburgh Instruments is located at the fourth floor of the Department of Chemical Sciences (lab 215 04 044). The instrument is a modular fluorescence and phosphorescence spectrometer for measuring steady-state spectra from the ultraviolet to the mid-infrared spectral range (up to 1700 nm), and time-resolved lifetimes spanning from picoseconds to seconds.
The FLS1000 is equipped with different excitation sources: 450 W Xenon Arc lamp for steady state measurements, a microsecond flashlamp, two pulsed light emitting diodes (LED, at 280 and 340 nm), and three pulsed diode lasers (at 405, 635 and 785 nm) for time-resolved luminescence investigation. It is equipped with double grating monochromators (emission and excitation), which guarantee high sensitivity. FLS1000 is also equipped with three detectors: the PMT-980 covers a range from 185 nm - 980 nm with instrument response of 600 ps, the high speed PMT covers the range from 200 nm - 850 nm with instrument response <200 ps, and the NIR-PMT, in liquid nitrogen cooled housing, covers the range from 500 to 1700 nm with photon counting sensitivity and speed. The FLS1000 has a large sample chamber and it is equipped with different sample holders that allow the analysis of solutions, films, powders; for solutions, a Peltier controlled holder allows measurement under controlled temperature in the range -40 ÷ 105 °C. Absolute emission quantum yield measurement of solution, thin-film and powder can be achieved by using the integrating sphere accessory.
In addition, fluorescence anisotropy measurements (steady-state and time-resolved) can be achieved by using excitation and emission polarizers in a range from 210 to 1700 nm.
contacts: sara.bonacchi@unipd.it ; ilaria.fortunati@unipd.it
location: 00 215 04 044
Agilent Cary Eclipse
Agilent Cary Eclipse is a fluorescence spectrophotometer with temperature control of the sample compartment.
contacts: leonard.prins@unipd.it
location at DiSC: 170-03-006
Perkin Elmer LS55 with temperature control of the sample compartment.
contacts: fabrizio.mancin@unipd.it
location at DiSC: 170-03-006
LS50B Fluorimeter
The LS50B luminescence spectrophotometer is equipped with a pulsed xenon lamp and temperature control of the sample compartment. Polarizers can be applied both to the exciting and to the scattered radiation beams. The exciting wavelenght and the collected scattered radiation range from 200 nm to 900 nm. The spectral bandwidth for the exciting radiation extends from 2.5 to 15 nm, while the emission can be detected from 2.5 to 20 nm. The equipment is particularly suitable for the study of protein conformations, while it can be declined in a wide range of experimental setup. A permanent senior technical staff manages the equipment, allowing reserachers to adapt it to their particular requests, giving students training and offering services to external industry when possible.
contacts: renato.schiesari@unipd.it
location at DiSC: 215-03-073
Horiba Fluorolog3 Spectrofluorimeter
The instrument is equipped with double-grating monochromator on both the excitation and emission sides coupled to a R928P Hamamatsu photomultiplier and a 450 W Xe arc lamp as the excitation source. Phosophorescence spectra can be acquired with the same instrument employing a pulsed Xe lamp. Lifetime measurements down to few nanoseconds can be achieved through Time Correlated Single Photon Counting (TCSPC) using pulsed nanoleds as excitation source. Absolute photoluminescence quantum yields can be measured by means of a Spectralon coated integrating sphere accessory (4", F-3018, Horiba Jobin Yvon), fitted in the fluorometer sample chamber. The instrument can operate from 290 nm to 850 nm at variable temperature from 77 K to 600 K.
contacts: gregorio.bottaro@cnr.it
location at DiSC: 215-01-036
Surface Plasmon Resonance (SPR)
Biacore X100
Surface plasmons change their resonance wavelength according to binding phenomena of molecules flowing onto the gold surface. On the basis of this phenomenon the Biacore X100 SPR allows to study interactions involving (in principle) any kind of molecule in any type of mixture.
contacts: fabrizio.mancin@unipd.it
location at DiSC: 170-00-010
Light Scattering
Light Scattering facility at DiSC is performed by the:
Malvern ZS nano Dynamic Light Scattering (DLS) and Zeta potential equipment
The Light Scattering spectroscopy performed by the Malvern ZS nano DLS allows to determine the dimensions of dissolved and suspended particles in the range from 2 to 1000 nm, while controlling the temperature of the sample compartment. Furthermore the Zeta Potential can be measured by electrophoretic light scattering from particles, molecules and surfaces.
contacts: fabrizio.mancin@unipd.it
location at DiSC: 170-00-010
