Didactic Experiments Using Voltammetric Measurements

Author: João Carlos de Andrade; Audrey de Arruda Falcão; Elaine Castilho Guedes
April 2007

Some analytical techniques, such as voltammetry, are relatively little used in undergraduate experimental disciplines in chemistry (and related sciences), although addressed in theoretical ones. Since, in contrast to what one thinks, voltammetric measurements are still often used in routine analysis, some of the most direct techniques will be highlighted in this text, with suggestions to [...]

Basic Principles of XAS and XPS

Author: Emerson Schwingel Ribeiro; Maria Suzana P. Francisco; José Eduardo Gonçalves; Yoshitaka Gushikem
February 2003

The basic principles of the X-ray absorption and photoelectronic spectroscopy (XAS and XPS), the equipment associated with these techniques and the methods employed for data processing are introduced. Emphasis is given to studies of electronic and structural properties of inorganic materials by describing some examples found in the literature. These techniques provide different information. The [...]

Electronic Absorption Spectroscopy

Author: Teresa D. Z. Atvars; Cláudia Martelli
February 2002

This text presents, briefly, the principles of operation of spectrophotometers for obtaining electronic absorption spectra from the ultraviolet spectral region to the near infrared. The layout and description of single and double beam optical instruments, as well as those which make use of photodiodearrays and photomultipliers as detectors.. This text will be supplemented by another, [...]

Luminescence Spectroscopy

Author: Teresa D. Z. Atvars; Cláudia Martelli

This text presents, briefly, the theoretical principles of the luminescence spectroscopy of organic molecules from an excited electronic state. For this a brief review of the processes of absorption on the vibrational structure of electronic transitions and the dependence of luminescence intensity on the concentration of the sample is presented. This matter also presents the [...]

Electronic Emission Spectroscopy

Author: Teresa D. Z. Atvars; Cláudia Martelli
February 2002

This article presents briefly the operating principles of a spectrofluorimeter used to obtain emission and excitation electronic spectra, from the ultraviolet to the near infrared spectral regions. It is also presents the usual layout of this kind of instrument for operation in photostationary conditions, as well as a description of its main components. The differences [...]

Fundamental Concepts in Spectroscopy

Author: Adalberto B. M. S. Bassi
September 2001

The effects resulting from the interaction of electromagnetic radiation with matter provide evidence for microscopic behavior. These observations lead us to propose models that enable understanding or predicting the properties of the material studied. Usually these models are associated with principles and concepts related to quantum mechanics. This topic will present the basic concepts necessary [...]

Law for the Processes of Absorption of Radiation

Author: Rogério Custodio; Lauro T. Kubota; João Carlos de Andrade
March 2000

Electromagnetic radiation absorbed by a sample may reveal some of its characteristics. Beer’s law establishes a linear relationship between absorbance and sample concentration. Therefore, it is possible to determine sample concentration through a calibration curve (absorbance versus concentration).
Beer- Lambert law, Beer’s law, transmittance, absorbance, intensity of radiation, monochromatic radiation, UV-Vis, spectrometer, calibration, concentration
Rogério Custodio
Lauro T. [...]