Reflection Absorption Infrared Spectroscopy (RAIRS-FTIR) is a highly sensitive technique used to analyze ultra-thin films and molecules on metal surfaces. It directs infrared light at a shallow angle to the surface. The light reflects off the metal and detects the exact chemical composition of the surface layer.

          Seagull Accessory           

How RAIRS-FTIR Works

  • Infrared Light: The machine shines infrared light onto a sample.
  • Molecular Vibration: When the light hits the molecules, the chemical bonds vibrate.
  • Reflection: The light reflects off the metal surface and goes to a detector.
  • The “Fingerprint”: The detector measures which light wavelengths are absorbed. This creates a unique pattern, just like a human fingerprint.

Why Choose RAIRS-FTIR?

  • Ultra-Thin Sensitivity: It can detect layers of molecules that are only a few atoms thick.
  • Non-Destructive: The test does not damage the sample.
  • Real-Time Analysis: Scientists can watch chemical reactions happen on a surface as they occur.

Common Uses

  • Surface Chemistry: Studying how coatings or lubricants stick to metals.
  • Corrosion Studies: Understanding how metals rust on a molecular level.
  • Catalysis Research: Testing materials used to speed up chemical reactions in green energy and fuel.

RAIRS vs. Standard FTIR

Standard FTIR (like ATR) usually tests bulk liquids or powders. RAIRS is specifically designed for thin layers on highly reflective metal surfaces.

Figure:  RAIRS-FTIR spectrum of 30 bilayers BSA-CS, θ = 0 incidence,  s polarization

Features

  • Multi-purpose, variable angle reflection attachment.
  • ATR, specular (external), and diffuse reflectance capabilities.
  • Continuously variable angle of incidence, from 5° to 85°.
  • Focuses the incident FT-IR beam on the sample for all incident angles.
  • Always centers the incident beam on the same area of the sample.
  • Direct angular read-out for all measurements; no ATR angle correction needed.
  • Maintains polarization for incident angles.
  • No realignment of the accessory or repositioning of the sample required when varying the incident angle.
  • High optical throughput.