Black-body infrared dissociation

Spectroscopy in the hydrogen-stretching region was applied to characterize proton and lithium-ion complexed valine complexes as a function of hydration with up to four water molecules [22], Although calculations and prior study by black-body infrared dissociation had suggested the possibility of zwitterions,... 

Black-body infrared radiative dissociation (BIRD) [88], which takes advantage of the photon flux of the black-body field generated by the vacuum chamber walls. The efficiency of BIRD depends on the temperature of the vacuum chamber and the ion storage time (typically 10-1000 s). 

BIRD black-body infrared radiative dissociation... 

Activation of the vibrational energy of ions can also be induced by the absorption of IR radiations. A popular type of IR radiation source is far-IR laser. In fact, many molecules have a broad IR absorption band. The most widely used IR source is a continuous wave (c.w.) CO2 laser, with the wavelength of 10.6 pm. This wavelength corresponds to an energy of 0.3 eV per laser photon. Because decomposition of a chemical bond requires >1 eV, laser excitation has to extended over hundreds of milliseconds to allow ions to absorb multiple IR photons. This method is known as infrared multiphoton dissociation (IRMPD). Another type of similar technique is black-body infrared radiative dissociation... 

In an FT-ICR instrument, fragmentation may be achieved by colliding ions with neutrals (CID) but various other strategies are available, such as collision with surfaces (surface-induced dissociation) or bombardment with ultraviolet or infrared radiation from a laser (ultraviolet photodissociation and multiphoton infrared photodissociation). Dissociation may also be achieved by the absorption of black-body radiation produced by a heated vacuum chamber walls (blackbody infrared dissociation). An advantage of these radiation-induced fragmentation methods is that gas pulses are no longer required. Sustained off-resonance irradiation is the preferred, radiation-based method for FT-ICR MS because it is the simplest to implement and tune. Very low energy and multiple excitation collisional activation techniques are also available. 

Even under essentially perfect vacuum where collisional activation is virtually absent (< 10 mbar) ions can undergo slow unimolecular dissociation. As the energy for these fragmentations is provided by the emission of infrared photons by black-body radiation of the vacuum housing, this process is termed blackbody infrared radiative dissociation (BIRD) [157]. Blackbody infrared radiation is always present above non-zero temperatures. BIRD dissociations are characterized by reaction times in the order of several seconds to even minutes. Therefore, ICR cells provide the most suitable environment for their study. To vary the wavelength and intensity of IR radiation both the ICR cell and the surrounding vacuum manifold have to be uniformly heated. Typically, temperatures up to about 250°C can be reached in dedicated instruments. This allows to study reaction kinetics where bonds of low to moderate strength are involved [157]. 

---