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Hello, my name is Renato Torre and I am a professor at the University of Firenze in Italy. My research deals with complex materials, mainly soft matter by laser spectroscopy. In this site you can find a short summary of my present and past work. I am coordinating the Soft Matter Physics Group at the European Lab. for Non-Linear Spectroscopy (LENS).


Here there are my coordinates to contact me:

Renato Torre, PhD
European Lab. for Non-Linear Spectroscopy (LENS)
and Dpt. of Physics and Astronomy, Univ. of Firenze
Via Car
rara 1, 50019 Sesto Fiorentino, Firenze, Italy
Tel: #39-055-4572495; skype: rena.torre
torre@lens.unifi.it; renato.torre@unifi.it; 



You can also follow these links:

Torre at LENS ;    Torre at UNIFI   ;    

Publication and citations on:




New Research and Highlights


Time-domain THz spectroscopy of
bone tissue

New investigation techniques are constantly required to better characterize bone ultrastructure,
we provide an extended investigation of the vibrational features 
of bone tissue in the 0.1-3 THz frequency range by time-domain THz spectroscopy s
upported by a combination of X-ray diffraction and DFT-normal modes 
calculations. In particular, we investigate the effect of heating on bone tissue and synthetic calciumphosphates 
compounds with close structure and composition to bone mineral
. We thus demonstrate that the narrow vibrational
mode at 2.1 THz in bone samples exposed to thermal treatment 
from a lattice mode of stoichiometric hydroxyapatite. 
The THz spectral range therefore provides a clear signature of the crystalline state 
of the investigated bone tissue and could, therefore be used to monitor or identify structural 
transitions occurring in bone upon heating.


Time-domain THz spectroscopy of the characteristics of hydroxyapatite provides a signature of heating in bone tissue. 
Plazanet M, Tasseva J, Bartolini P, Taschin A, Torre R, Combes C, et al. 



THz
 investigation of Potential Qubits, 
Phonons and Spin Dynamics


The investigation of the magnetization dynamics of a vanadyl complex in both solid-state and frozen solution, showed an anomalous and unprecedentedly observed field dependence of the relaxation time. The temperature dependence of the weight of the processes was found to well correlate with the low energy vibrations as determined by THz spectroscopy. This detailed experimental comparative study represents a fundamental step to understand the spin dynamics of potential molecular quantum bits, and enriches the guidelines to design molecule-based systems with enhanced quantum coherence.



Structural Effects on the Spin Dynamics of Potential Molecular Qubits 
M. Atzori, S. Benci, E.Morra,
 
L. Tesi, M.Chiesa, 
Renato Torre, L. Sorace, and R. Sessoli

Spin Dynamics and Low Energy Vibrations: Insights from Vanadyl-Based Potential Molecular Qubits
M. Atzori, L. Tesi, S. Benci, A. Lunghi, R. Righini, A. Taschin, Renato Torre, L. Sorace, and R. Sessoli



Dynamics of Liquid Water: recent experimental investigations


The liquid and supercooled states of water show a series of anomalies whose nature is debated. A key role is attributed to the formation of structural aggregates induced by critical phenomena occurring deep in the supercooled region; the nature of the water anomalies and of the hidden critical processes remains elusive. We used a time-resolved optical Kerr effect investigation of the vibrational dynamics and relaxation processes in supercooled bulk water.

Recently, we presented an overview of  time-resolved vibrational spectroscopic studies of liquid water from ambient conditions to the supercooled state. The structure and dynamics of the complex hydrogen-bond network formed by water molecules are discussed, as well as the dissipation mechanism of vibrational energy throughout this network. A broad range of water investigations are addressed:infrared and Raman spectroscopy, femtosecond pump−probe, photon-echo, optical Kerr effect, sum-frequency generation, and two-dimensional infrared spectroscopic studies. By comparison of the complementary aspects probed by various linear and nonlinear spectroscopic techniques, a coherent picture of water dynamics and energetics emerges. 

Vibrational Spectroscopy and Dynamics of Water
Perakis, F.; Marco, L.; Shalit, A.; Tang, F.; Kann, Z. R.; Kuhne, T. D.; Torre, R.; Bonn, M.; Nagata, Y.

Optical Kerr Effect of Liquid and Supercooled Water: The Experimental and Data Analysis Perspective.
A. Taschin, P. Bartolini, R. Eramo, R. Righini, and R. Torre.
Journal of Chemical Physics,141 (2014) 084507.

Evidence of two distinct local structures of water from ambient to supercooled conditions. 
A.Taschin,P. Bartolini, R. Eramo, R. Righini, and R. Torre, 
Nat. Commun. 4 
(2013) 1–8 ,


Nanoconfined Water

We investigate the vibrational dynamics and the structural relaxation of water nanoconfined in Vycor porous silica samples (pore size 4 nm) at different levels of hydration and temperatures. At low level of hydration, corresponding to two complete superficial water layers, no freezing occurs and water remains mobile at all the investigated temperatures with dynamic features similar, but not equal, to the bulk water. The fully hydrated sample shows formation of ice at about 248 K, this processes does not involve all the contained water; a part of it remains in a supercooled phase.
The spectra are obtained as the Fourier transforms of time-resolved heterodyne detected optical Kerr effect (HD-OKE) measurements. The comparison of these spectra with that of bulk water enables us to separately extract and analyze the spectral contributions of the first and second hydration layers, as well as that of bulk-like inner water. We conclude that the extra water entering the pores above ≈ 10 % water/silica weight ratio behaves very similarly to bulk water. At lower levels of hydration, corresponding to two complete superficial water layers or less, the H-bond bending and stretching bands, characteristic of the tetrahedral coordination of water in the bulk phase, progressively disappear: clearly in these conditions the H-bond connectivity is very different from that of liquid water.

THz Dynamics of Nanoconfined Water by Ultrafast Optical Spectroscopy,
Taschin A.,  Bartolini P. and Torre R.

Confinement, entropic effects and hydrogen bond network fluctuations of water in Nafion membrane
Plazanet, M.,  Torre, R.,  Sacchetti, F. 

Supercooling and Freezing Processes in Nanoconfined Water by Time-Resolved Optical Kerr Effect Spectroscopy
A.Taschin,  P. Bartolini, A. Marcelli, R. Righini, and R. Torre. 

A comparative study on bulk and nanoconfined water by time-resolved optical Kerr effect spectroscopy
A. Taschin, P. Bartolini, A. Marcelli, R. Righini,  & R. Torre.



THz radiation and artwork investigations


THz pulse imaging and spectroscopy is an emerging non-invasive method for the char
acterization of cultural heritage artefacts that provides complementary information to tra
ditional analytical tools.
We explored artworks drawing materials with THz-Time Domain Spectro
scopy (THz-TDS) extending the investigation to thin layers of inks, that was never realized 
previously. We developed a new speci.c experimental method and data analysis to disen
tangle the multiple re
ection signals. Thanks to a high signal to noise ratio and the accurate 
analysis implemented, our measurements enable the calculation of the absolute absorption 
coeffi.cient and index of refraction of the materials, as well as the sample thickness down to 
tens of microns both in single layer and bilayer con.gurations.


THz time-domain spectroscopic investigations of thin films.
Taschin, A.; Bartolini, P.; Tasseva, J.; Torre, R. 
Measurement, 118 (2018), 282-288

Drawing materials studied by THz spectroscopy.
Andrea Taschin; Paolo Bartolini; Jordanka Tasseva; Jana Striova; Raffaella Fontana; Cristiano Riminesi; Renato Torre.
Acta Imeko, 6 (2017) 12-17

Thin layered drawing media probed by THz time-domain spectroscopy
J. Tasseva, A. Taschin, P. Bartolini, J. Striova, R. Fontana, R. Torre
Analyst 142 (2017) 42-47


Second-harmonic generation from plasmon 
polariton

We present a comparison between experimental and theoretical results for the diffraction efficiencies of the second harmonic 
light produced in the orders of silver diffraction gratings. The gratings considered are sinusoidal, have 
depths of a few nanometers, and can produce significant surface plasmon polariton excitation at fundamental and 
second-harmonic frequencies. The calculations are based on a general expression for the nonlinear polarization of 
the surface of a homogeneous and isotropic medium, and the diffraction problems at the fundamental and harmonic 
frequencies are solved using a Rayleigh method.



Second-harmonic generation from plasmon polariton excitation on silver diffraction gratings: comparisons of theory and experiment.
M.E. Inchaussandague, M. L. Gigli, K. A. O’Donnell, E.R. Mendez, R. Torre and C.I. Valencia


Cryotechniques

I
n this study, a novel cryopreservation technique based on a rapid cooling procedure was applied to adults of C. elegans, a complex metazoan organism, the nematodes survive to a rapid cooling and storage in liquid nitrogen (−196 °C) with a very high survival percentage (85%). The procedure relies on low cryoprotectant percentage and ultra rapid cooling technique. The high cooling rate is achieved through the reduction of sample volumes and the effectiveness of a nylon carrier. Our technique complies with the requirements for vitrification. Our results show that this cryopreservation method is valid for both unicellular and multicellular organisms; it is suitable for short or long time storage in liquid-nitrogen. This technique promises to be a unique and simpler method for cryostorage of cells, organisms and tissues.

An ultra-rapid cryo-technique for complex organisms
Irdani, T.; Fortunato, A.; Torre, R.




High-Precision Terahertz Spectroscopy

Trace-gas sensing with high sensitivity and precision in the terahertz regime can be important in environmental monitoring, security, and astrophysics, as well as in tests of fundamental physics. Now, as reported in Physical Review X, a research team has performed the first terahertz spectroscopic measurements using a so-called frequency comb—a technique that allows frequency measurements with extremely high accuracy. As a proof-of-principle, the team measured a rotational transition in a gas molecule (methanol) to a precision of 4 parts in one billion, 10 times better than the previous record. The result is also twice as precise as the theoretically predicted frequency, suggesting the technique could help refine theoretical models.



Frequency-Comb-Assisted Terahertz Quantum Cascade Laser Spectroscopy
S. Bartalini, L. Consolino, P. Cancio, P. De Natale, P. Bartolini, A. Taschin, M. De Pas, H. Beere, D. Ritchie, M. S. Vitiello, and R. Torre
Phys. Rev. X 4, 021006 (2014)







Ċ
Renato Torre,
24 Oct 2017, 03:23