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Two-dimensional infrared spectroscopy (2D IR) is a nonlinear infrared spectroscopy technique that has the ability to correlate vibrational modes in condensed-phase systems. This technique provides information beyond linear infrared spectra, by spreading the vibrational information along multiple axes, yielding a frequency correlation spectrum.
The nonlinear two-dimensional infrared spectrum is a two-dimensional correlation plot of the frequency ω 1 that was excited by the initial pump pulses and the frequency ω 3 excited by the probe pulse after the waiting time. This allows the observation of coupling between different vibrational modes; because of its extremely fine time ...
An operator uses a series of 4-bar targets of different spatial frequencies. For each target he/she adjusts the blackbody, (source of Infrared radiation), temperature up and down until the pattern is "just resolvable." The positive and negative temperature differences are stored into a two dimensional array. The corresponding spatial ...
At any given temperature, there is a frequency f max at which the power emitted is a maximum. Wien's displacement law, and the fact that the frequency is inversely proportional to the wavelength, indicates that the peak frequency f max is proportional to the absolute temperature T of the black body. The photosphere of the sun, at a temperature ...
The term electronic refers to the fact that the optical frequencies in the visible spectral range are used to excite electronic energy states of the system; however, such a technique is also used in the IR optical range (excitation of vibrational states) and in this case the method is called two-dimensional infrared spectroscopy (2DIR). [2]
For example, a wavenumber in inverse centimeters can be converted to a frequency expressed in the unit gigahertz by multiplying by 29.979 2458 cm/ns (the speed of light, in centimeters per nanosecond); [5] conversely, an electromagnetic wave at 29.9792458 GHz has a wavelength of 1 cm in free space.
two bands (distinct from ketones, which do not possess a C─O bond) C─N aliphatic amines any 1020–1220 often overlapped C═N any 1615–1700 similar conjugation effects to C═O C≡N unconjugated 2250 medium conjugated 2230 medium R─N─C (isocyanides) any 2165–2110 R─N═C═S (isothiocyanates) any 2140–1990 C─X
The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band. From low to high frequency these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. The electromagnetic waves in each of these bands have different characteristics, such as how they are ...