Pike Technologies Comprehensive Catalog of FTIR ... - Madatec

More documents

Recommendations

Info

Specular Reflectance – Theory and Applications Specular reflectance sampling in FTIR represents a very important technique useful for measurement of thin films on reflective substrates, analysis of bulk materials and measurement of monomolecular layers on a substrate material. Often the specular reflectance technique provides a means of sample analysis with no sample preparation – keeping the sample intact for other measurements. The basics of the sampling technique involve measurement of the reflected energy from a sample surface at a given angle of incidence. The electromagnetic and physical phenomena which occur at and near the surface are dependent upon the angle of incidence of the illuminating beam, refractive index and thickness of the sample and other sample and experimental conditions. A discussion of all of the physical parameters and considerations surrounding the specular reflectance sampling technique is beyond the scope of this overview. We will present the specular reflectance sampling technique from an applications oriented perspective. Types of specular reflectance experiments • Reflection-Absorption of relatively thin films on reflective substrates measured at near normal angle of incidence • Specular Reflectance measurements of relatively thick samples measured at near normal angle of incidence • Grazing Angle Reflection-Absorption of ultra-thin films or monolayers deposited on surfaces measured at high angle of incidence In the case of a relatively thin film on a reflective substrate, the specular reflectance experiment may be thought of as similar to a “double-pass transmission” measurement and can be represented as shown in the following illustration; At the reflective substrate, the beam reflects back to the surface of the thin film. When the beam exits the thin film it has geometrically passed through the film twice and is now represented as I A . Infrared energy is absorbed at characteristic wavelengths as this beam passes through the thin film and its spectrum is recorded. The specular reflectance spectra produced from relatively thin films on reflective substrates measured at near-normal angle of incidence are typically of high quality and very similar to spectra obtained from a transmission measurement. This result is expected as the intensity of I A is high relative to the specular component, I R . Spectrum of thin film coating on a metal surface measured at 30 degrees angle of incidence using the VeeMAX II specular reflectance accessory For relatively thick samples, the specular reflectance experiment produces results which require additional considerations as the specular component of the total reflected radiation is relatively high. Again, the incident FTIR beam represented by I 0 illuminates the sample of a given refractive index, n 2 and at an angle of incidence, θ 1 . Some of the incident beam is reflected from the sample surface, represented by I R at the incident angle, θ 1 . Some of the incident beam is transmitted into the sample represented by I T at an angle of θ 2 . As predicted by Fresnel equations, the percent of reflected vs. transmitted light increases with higher angles of incidence of the illuminating beam. Furthermore, the refractive index of the sample, surface roughness and sample absorption coefficient at a given wavelength all contribute to the intensity of the reflected beam. S PECULAR R EFLECTANCE P RODUCTS – T HIN F ILMS AND M ORE Beam path for Reflection-Absorption of a relatively thin film measured by Specular Reflectance The incident FTIR beam represented by I 0 illuminates the thin film of a given refractive index, n 2 and at an angle of incidence, θ 1 . Some of the incident beam is reflected from the sample surface, represented by I R at the incident angle, θ 1 and is also known as the specular component. Some of the incident beam is transmitted into the sample represented by I T at an angle of θ 2 – calculated from Snell’s Law. n 1 sinθ 1 = n 2 sinθ 2 Beam path for a relatively thick sample measured by Specular Reflection 45
P IKE T ECHNOLOGIES WWW. PIKETECH. COM 608-274 2721 At wavelengths where the sample exhibits a strong IR absorption, the reflectivity of the sample increases. The superposition of the extinction coefficient spectrum with the refractive index dispersion results in a spectrum with derivative shaped bands. This specular reflection spectrum can be transformed using a Kramers-Kronig conversion to a transmission-like spectrum as shown in the example below. Spectrum (upper – original) of a relatively thick polymer sample measured at 30 degrees angle of incidence using the VeeMAX II. The lower spectrum has been transformed using the Kramers-Kronig software algorithm and is very similar to a transmission spectrum of the polymer – polyethylene. Our third application of specular reflectance is the measurement of relatively thin films and mono-molecular layers at grazing angle of incidence. At high angles of incidence, between 60 and 85 degrees, the electromagnetic field in the plane of the incident and reflected radiation is greatly increased relative to a near normal angle of incidence. The perpendicular component of the electromagnetic field of the reflecting radiation is not enhanced. Because of the orientation of the electro-magnetic field at the surface for grazing angle measurements, the use of an IR polarizer greatly improves the sampling result. By collecting the spectrum at grazing angle of incidence with P-polarization, we only examine the enhanced portion of the electromagnetic field at the sample surface, thereby producing a stronger absorbance spectrum. Grazing angle specular reflection analysis of a thiol mono-molecular layer deposited on a gold surfaced mirror using the PIKE VeeMAX II at 80 degrees and P-polarization. The FTIR was equipped with an MCT detector. Specular reflectance is a valuable FTIR sampling technique for the analysis of thin films on reflective substrates, for the analysis of relatively thick films on reflective materials and for analysis of bulk materials where no sample preparation is preferred. PIKE Technologies offers a complete line of specular reflectance accessories and options to do these analysis and perform these experiments. Grazing angle specular reflection analysis produces a strong electromagnetic field oriented in the plane of the incident and reflected radiation 46
Page 2 and 3: FTIR Instrument Code XX ABB Bomem F
Page 4 and 5: TABLE O F C ONTENTS Pages 1 - 6 Pag
Page 6 and 7: Sampling Kits If you are not sure w
Page 8 and 9: Comprehensive Transmission Sampling
Page 10 and 11: Valu-Line - High Performance Set of
Page 12 and 13: Attenuated Total Reflectance Sampli
Page 14 and 15: Table 1: MIRacle Crystal Plate Spec
Page 16 and 17: MIRacle Base Optics (must select, i
Page 18 and 19: GladiATR Base Optics (must select,
Page 20 and 21: HATR Crystal Plate Choices PIKE Tec
Page 22 and 23: HATR and HATRPlus Pressure Clamp (m
Page 24 and 25: Optimized FTIR spectrum of polymer
Page 26 and 27: VeeMAX II with ATR - Variable Angle
Page 28 and 29: Classic VATR - Variable Angle ATR f
Page 30 and 31: Table 1 ATR Sampling ZnSe, Diamond
Page 32 and 33: Diffuse Reflectance Products Diffus
Page 34 and 35: DiffusIR - Research Grade Diffuse R
Page 36 and 37: UpIR - Upward Looking Diffuse Refle
Page 38 and 39: X, Y Autosampler - Transmission and
Page 40 and 41: Diffuse Reflectance - Theory and Ap
Page 42 and 43: Specular Reflectance Products Specu
Page 44 and 45: Changing the angle of incidence wit
Page 46 and 47: 80Spec - Grazing Angle Specular Ref
Page 48 and 49: 10Spec - Measures Sample Reflectanc
Page 52 and 53: Polarization Products Polarizers ma
Page 54 and 55: Infrared Polarizers - Theory and Ap
Page 56 and 57: Integrating Sphere Products Integra
Page 58 and 59: NIR IntegratIR - Integrating Sphere
Page 60 and 61: Integrating Spheres - Introduction
Page 62 and 63: Fiber Optic Sampling Products Fiber
Page 64 and 65: FlexIR - NIR Fiber Optic Accessory
Page 66 and 67: Microsampling Products Microsamplin
Page 68 and 69: Switching from transmission to refl
Page 70 and 71: Microsampling Tools - Compression C
Page 72 and 73: Beam Condensers - 4X and 6X Version
Page 74 and 75: Transmission Sampling Products Tran
Page 76 and 77: RotatIR - Automated Rotating Sample
Page 78 and 79: X, Y Autosampler - Transmission and
Page 80 and 81: Demountable Liquid Cells - For Vers
Page 82 and 83: Long-Path Quartz Liquid Cells - For
Page 84 and 85: Demountable Liquid Cell Windows (mu
Page 86 and 87: Bolt Press & Hydraulic Die - Low-Co
Page 88 and 89: PIKE CrushIR - Digital Hydraulic Pr
Page 90 and 91: Sample Preparation Accessories - Fo
Page 92 and 93: Disks, Windows and Powders - For Tr
Page 94 and 95: Disks, 41 mm Diameter 3 mm Thicknes
Page 96 and 97: Short Path Gas Cells - For Samples
Page 98 and 99: Long-Path Gas Cells - For Measureme
Page 100 and 101:
Transmission Sampling Techniques -
Page 102 and 103:
An alternate method for analysis of
Page 104 and 105:
Special Applications Products PIKE
Page 106 and 107:
MappIR and MAP300 - For Automated A
Page 108 and 109:
TGA/FTIR Accessory - Identification
Page 110 and 111:
Semiconductor Applications - FTIR S
Page 112 and 113:
Other Useful Products for Spectrosc
Page 114 and 115:
ATR spectra are somewhat different
Page 116 and 117:
ATR Spectral Data Bases - Optimize
Page 118 and 119:
Alphabetical Index A 10Spec, specul
Page 120 and 121:
T Teflon gaskets, demountable cell
Page 122 and 123:
022-5340 HATR Liquid Jacketed Troug
Page 124 and 125:
160-1007 25 x 2 mm ZnSe (6 pack) 88
Page 126 and 127:
162-1130 Press-On Demountable Liqui
Page 128:
We are PIKE Technologies, a small c
show all

Pike Technologies Comprehensive Catalog of FTIR ... - Madatec

Create successful ePaper yourself

Delete template?

Save as template?