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IR Spectrometers

IR Spectrometers

There are two main infrared (IR) spectrophotometers: dispersive IR spectrometers and Fourier transform infrared (FTIR) spectrometers. In a dispersive IR spectrometer, a beam of infrared radiation produced by a hot wire is divided into two parallel equal-intensity beams using mirrors. One beam passes through the sample, while another is a reference beam. The beams then move through the monochromator, which separates the radiations into a continuous spectrum of different frequencies. The...

Infrared (IR) Spectroscopy: Overview

Infrared (IR) Spectroscopy: Overview

When electromagnetic radiation passes through a material, atoms or molecules transition from a lower to a higher energy state by absorbing radiation corresponding to the energy difference between the two states. The absorption of infrared (IR) radiation causes transitions between vibrational energy levels in a molecule. Therefore, IR spectroscopy is a useful analytical tool for determining the molecular structure of molecules.
Different compounds display unique properties due to their...

IR Spectroscopy: Molecular Vibration Overview

IR Spectroscopy: Molecular Vibration Overview

When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental vibrational motions that result in infrared absorption can be classified as stretching or bending vibrations.
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...

IR Frequency Region: Fingerprint Region

IR Frequency Region: Fingerprint Region

IR spectra are divided into two main regions: the diagnostic region and the fingerprint region. The diagnostic region of the spectrum lies above 1500 cm−1. The absorptions resulting from single-bond vibrations of the N–H, C–H, and O–H stretch at higher wavenumbers and appear on the left side of the spectrum. The stretching absorptions of the C≡C and C≡N occur between 2100–2300 cm−1. In contrast, those arising from stretching absorptions of the C=O, C=N, and C=C occur between 1600–1850 cm−1.
The...

Applications of IR Spectroscopy: Overview

Applications of IR Spectroscopy: Overview

The non-destructive nature and ability to provide valuable chemical information make IR spectroscopy a versatile technique with broad applications in various scientific and industrial fields. IR spectroscopy is commonly used to identify and characterize organic and inorganic compounds. It provides information about the functional groups present in a molecule and the bonding between atoms. This helps in the structural elucidation of compounds during organic synthesis, pharmaceutical research,...

Raman Spectroscopy Instrumentation: Overview

Raman Spectroscopy Instrumentation: Overview

A conventional Raman spectrophotometer includes a laser source, a sample holding system, a wavelength selector, and a detector.
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...

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High-definition Fourier Transform Infrared (FT-IR) Spectroscopic Imaging of Human Tissue Sections towards Improving Pathology

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A double beam, high resolution spectrometerfor the far infrared.

T M Hard¹, R C Lord

¹MIT Spectroscopy Laboratory, Cambridge, Massachusetts 02139, USA.

|January 14, 2010

Summary

A new far infrared spectrometer was developed for molecular spectroscopy. This instrument achieves high resolution for analyzing gaseous polyatomic molecules in the 20-300 cm(-1) range.

Area of Science:

Spectroscopy
Molecular Physics
Infrared Technology

Background:

Far infrared (FIR) spectroscopy is crucial for understanding molecular vibrations and structures.
Previous instruments had limitations in resolution and spectral range for FIR analysis.
Development of advanced spectrometers is essential for detailed molecular characterization.

Purpose of the Study:

To construct and characterize a novel far infrared spectrometer.
To achieve high spectral resolution for analyzing gaseous polyatomic molecules.
To demonstrate the instrument's capability in the 20-300 cm(-1) spectral region.

Main Methods:

Utilized an Ebert-Fastie monochromator with 1.8-m focal length plane gratings (19 cm x 13 cm).
Employed a double-beam optical system with electronic ratio recording for precise measurements.

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A Multimodal Wide-Field Fourier-Transform Raman Microscope

A Multimodal Wide-Field Fourier-Transform Raman Microscope

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Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

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Used a liquid helium-cooled gallium-doped germanium bolometer as the detector.

Main Results:

Achieved spectral resolution ranging from 0.1 cm(-1) to 0.4 cm(-1) using four different gratings.
Successfully minimized unwanted radiation to 1% or less in most spectral ranges via filter combinations.
Demonstrated the spectrometer's performance by obtaining spectra of gaseous polyatomic molecules.

Conclusions:

The constructed far infrared spectrometer is a capable instrument for high-resolution molecular spectroscopy.
The instrument's performance covers the essential 20-300 cm(-1) range for FIR studies.
This development provides a valuable tool for the detailed analysis of gaseous polyatomic molecules.