15 Questions 714 Answers 0 Followers
Questions related from Thomas Mayerhöfer
In particular if infrared spectroscopy is applied to organic or biologic materials, absorbance spectra are usually not processed by dispersion analysis or Kramers-Kronig analysis to obtain the...
05 November 2017 2,248 1 View
Most types of spectrometer measure either transmittance or reflectance (to be more precise, they measure the number of photons that reach the detector and not the ones which are absorbed). There...
26 May 2017 6,395 31 View
We recently examined the validity of the relation -log T = A and found that this relation is widely inadequate for pure substances/films (see link). Since those are quite often used in CD/VCD...
22 May 2016 2,841 0 View
According to Bohren and Huffman, Scattering by a collection of randomly oriented anisotropic spheres is given by: = 1/3 C1+1/3 C2+1/3 C3, "where Cj is the cross section for an isotropic...
30 December 2015 7,757 2 View
I opt for renaming the (Bouguer-)Beer-Lambert (BBL) law and suggest "Ideal absorption law". Why? There are many parallels between the ideal gas law and the ideal absorption law, e.g. that both are...
01 January 1970 1,017 5 View
Sometimes you find the argument in literature that at high angle of incidence alpha (say, 80°) and p-polarized light an important factor for the comparable high signal in transflection...
01 January 1970 6,424 5 View
If a non-absorbing film is put on a perfect electric conductor the reflectivity of the system is still unity. In case of real metals, interference effects become obvious through interference...
01 January 1970 8,663 19 View
E.g. in surface enhanced infrared spectroscopy it is quite often claimed that absorbance or extinction defined as A = -lg T (where T is the transmittance) is proportional to the electric Field...
01 January 1970 793 8 View
Having "grown up" with absorbance I get more and more concerned about the damage that the use of this quantity does and has already done (being not conform with Maxwell's equations, at least in...
01 January 1970 3,983 11 View
About 20 years ago I came across a problem that made me giving up Linear Dichroism Theory (LDT), but during a discussion in another thread the replacement theory raised doubts. Maybe my knowledge...
01 January 1970 559 3 View
Here is a little problem I came across yesterday in a discussion that I thought interesting enough to share with the RG community. Assume you have measured a thin layer of an organic material on...
01 January 1970 1,956 15 View
In case of attenuated total reflection (ATR), absorbance can be calculated by -log(R/R0) where R0 is the signal of the ATR crystal without sample. If -log(R/R0) is compared to -log T from...
01 January 1970 2,040 16 View
Heinrich Rubens, Marianus Czerny, Clemens Schaefer, Frank Matossi and what they stand for? Why do you think that in articles like Technological Innovation in Science: The Adoption of Infrare... a...
01 January 1970 4,684 9 View
Quantum mechanical calculations of infrared spectra return the absorption coefficient times the refractive index, which is effectively the dielectric function. But this result is compared with...
01 January 1970 3,823 2 View
Starting with the end of the 50ies of the last century, it was assumed that determining not only the band positions, but also intensities would be a big step forward for infrared spectroscopy. Why...
01 January 1970 4,827 13 View
