Schema della sezione

  • Welcome.

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  • Introduction

    Welcome to the website of the course Spectroscopic Methods for Materials Characterization – Optical Spectroscopy Part (3 ECTS).
    Optical spectroscopy in general, and in particular microscopy and imaging techniques based on it, have become a common resource in many advanced materials science laboratories.

    The course is designed as an introduction to optical spectroscopy and as a “tutorial” on the main spectroscopic and advanced imaging techniques currently used in research and materials characterization laboratories.

    The aim is therefore to qualitatively introduce the fundamental concepts of spectroscopy and the related imaging techniques based on fluorescence (e.g., FLI, FRET, STED, two-photon fluorescence), infrared (FT-IR, ATR), and Raman spectroscopy (e.g., SERS), and then to examine examples of applications taken from recent scientific literature.

    The course also includes a visit to the fluorescence and Raman spectroscopy/imaging laboratory, with short demonstrations (in the presence of the instructor) of some of the techniques covered during the course.

  • Program

    For the complete program, please refer to the course syllabus.

    The basic structure of the course is divided into three parts, each lasting approximately 8 hours (for a total of 24 hours):

    1. General introduction to optical spectroscopy and biophotonics, including an overview of the interaction between radiation and matter, with particular reference to materials; an overview of the instrumentation used in optical spectroscopy, including a short practical activity in which students will build a mini spectroscope to observe spectra using their smartphone camera;

    2. Introduction to fluorescence, including basic theoretical concepts and numerous examples of applications taken from the scientific literature;

    3. Introduction to vibrational spectroscopies, including basic theoretical concepts and the introduction of spectroscopic and imaging techniques such as IR, Raman, and SERS.

     
     

  • Teaching materials

    Here you can download the slides used during the lectures, as well as any additional material made available by the instructor.

  • Bibliography

    As for reference texts, the course is built by drawing from various textbooks, such as for example:

    General introduction to methods and instrumentation in optical spectroscopy
    Skoog, West, Holler, Crouch, Fundamentals of Analytical Chemistry, Brooks/Cole, 2014 – (DIP. SCI. CHIMICHE DO 05./A / 0004; DO 04/32 / 0150)
    Harvey, Modern Analytical Chemistry, McGraw Hill, 2000

    Fluorescence
    Lakowicz, Principles of Fluorescence Spectroscopy, Springer, 2006 (DIP. SCI. CHIMICHE DO 04/06 / 0385)
    Valeur and Beberan-Santos, Molecular Fluorescence, Wiley-VCH, 2012 (DIP. SCI. CHIMICHE DO 04/06 / 0296)

    IR and Raman
    Larkin, IR and Raman Spectroscopy: Principles and Spectral Interpretation, Elsevier, 2011 (BIB. TECNICO SCIENTIFICA H0 33 / 0015)
    Smith and Dent, Modern Raman Spectroscopy: A Practical Approach, Wiley, 2005 (B. DIP. MAT. RISOR. NAT.-ING. MATERIALI 05./I /0012; DIP. SCI. CHIMICHE DO 04/06 /0336)
    Vandenabeele, Practical Raman Spectroscopy – An Introduction, Wiley, 2013

    Other texts for further study
    Pavia, Lampman, Kriz, Vyvyan, Introduction to Spectroscopy, Brooks/Cole, 2009

    The purchase of textbooks (which are often very expensive or out of print) is not required. The course can be followed using only the information provided during lectures and the slides. Some of these books are available in the University libraries (their locations are indicated after the bibliographic details), and upon request I can also make some of these texts available for consultation to interested students.

  • Assessment methods

    The exam will consist of:

    1. The presentation of a short experimental report (3–5 pages), written in groups of 3–5 students, on the activities carried out using the spectrograph. The report should include a brief introduction, a description of the instrument and the methods used (e.g., calibration), and a section describing the obtained data (acquired spectra, from at least three different sources/experiments), possibly with comments and discussion.

    2. The presentation and discussion of a scientific article, chosen by the student (but agreed upon with the instructor by e-mail at least one week before the exam), related to the topics covered in the course. The presentation will be in a seminar format, and students are encouraged to use PowerPoint or similar applications. All presentations will take place during a symposium day, in which all students are invited to participate.

    The reports in PDF format (file named “(surnames)_report.pdf”) should be sent by e-mail to the instructor (abonifacio@units.it) within one week from the exam date.

    The final grade (out of 30) will be calculated according to the following scheme:

    • Experimental report: from 10 to 14 points

    • Presentation: from 9 to 13 points

    • Answers to questions: from 1 to 3 points

    The exam dates for students enrolled in the course are published on ESSE3 or on the Department website. Students can register for the exam through the usual procedures via ESSE3. Extraordinary exam sessions may be arranged with the instructor.

  • Links

  • Software

    Per far girare lo script per trasformare le immagini di spettri in grafici (dati) XY sul proprio computer, seguire le istruzioni:


    1. Scaricare ed installare sul proprio computer il software gratuito R da www.r-project.org (Downoad > CRAN > ...)

    2. Scaricare ed installare l'interfaccia gratuita RStudio da www.rstudio.com

    3. Aprire RStudio, cliccare sulla tab "Packages" nel riquadro in basso a destra, cliccare "Install" ed installare i pacchetti "shiny", "imager" e "MALDIquant"

    4. Scaricare l'archivio app.ZIP da questo link (stessa password usata per scaricare le slides)

    5. Estrarre il contenuto dell'archivio in una cartella "specgraph" (da creare apposta sul proprio computer)

    6. Aprire il file app.R con RStudio, e cliccare il tasto "Run App" al centro in alto. 
        L'applicazione dovrebbe aprirsi nel browser di default.

    Poi basta seguire le solite istruzioni come indicate nella sezione "links".
    Lo script è stato testato sia su Windows che su Mac.

  • Tutorial per la calibrazione del mini-spettrografo

    Ecco alcune indicazioni sul come acquisire le immagini a righe ottenute dal proprio smartphone (intensità luce su pixels in x e y), ed elaborarle in spettri veri e propri (intensità luce vs. lunghezza d'onda in nm).

    1. fissare il mini-spettrografo sul proprio smartphone con il nastro adesivo;

    2. acquisire una immagine spettrale della luce emessa da una lampadina a fluorescenza (no LED, no incandescenza) dal proprio smartphone utilizzando il mini-spettrografo costruito. Questa immagine dovrebbe avere almeno 4 righe colorate ben visibili, e servirà a calibrare la camera del vostro smartphone per le prossime immagini che verranno acquisite;

    3. senza spostare la posizione del mini-spettrografo, acquisire in serie altre immagini spettrali da altre sorgenti di luce; ogni volta che il mini-spettrografo viene spostato o rimosso, la prima immagine a righe ad essere acquisita deve sempre essere quella di una lampada a fluorescenza;

    4. in caso, ruotare le immagini a righe in modo da avere una serie di righe verticali, con le righe blu a sinistra e quelle rosse a destra;

    5. per ogni immagine, caricarla (formato .jpg) nell' applicazione online per trasformare l' immagine a righe in spettro, e scaricare il file con i dati in formato ASCII da aprire poi in MS Excel; per lo spettro della lampadina a fluorescenza, prendere nota della posizione (in pixel) delle 4 bande più intense (serviranno per la calibrazione in Excel);


    FIGURA 2. Esempio di spettro ottenuto da una immagine a righe.


    6. Usare le posizioni delle bande della lampadina a fluorescenza (spettro noto, vedi figura 1) in excel per calibrare l'asse delle x (pixels), trasformandolo in lunghezza d'onda (nm), in modo da ottenere spettri Intensità/lunghezza d'onda (nm). Vedi figura 3.



    FIGURA 3. Esempio di utilizzo di MS Excel per calibrazione.


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