BIRD (blackbody infrared radiative dissociation): Evolution, principles, and applications
Authors: Dunbar Robert C. 
Published: January 2004

I.
Introduction
128

 II.
Brief History of the Development of BIRD
129

   1.  Dissociation by Ambient Radiation
129

   2.  The Rapid‐Exchange Limit
129

  III.
Experimental Approaches
130

  IV.
Fundamental Principles and Approaches to Interpretation
131

A.  Kinetics Considerations
132

B.  Large Molecules
134

   1.  When Is the Large‐Molecules Limit Achieved?
135

   2.  Small Molecules
137

   3.  Intermediate Size
138

 V.
Examples and Applications
140

A.  Proton‐Bound Dimers
140

B.  Solvent Detachment Studies
142

   1.  Small Solvated Ions
142

   2.  Deuteration Effects
142

   3.  Hydrated Metal Ions
143

   4.  Non‐Aqueous Solvents: Ru(bipy)+23 Complexes
143

C.  Silanes
145

D.  Zwitterions and Salt Bridges
146

E.  Metal‐Cationized Amino Acids
147

F.  Macrocycles
148

   1.  Iron Porphyrin Complexes
148

   2.  Hemoglobin/Myoglobin
148

G.  Nucleotides and Oligonucleotides
149

H.  Protein and Polypeptide Ions
149

I.  Protein Complexes
149

J.  Informative Fragmentations by BIRD Excitation
149

K.  Analyzing Ion Mixtures
150

 VI.
Water‐Cluster Ions
150

 VII.
Extensions and Analogs to BIRD for Activation Energy Measurement
151

A.  High‐Pressure Thermal Dissociation
152

   1.  Quadrupole Trap
152

   2.  Hot Reaction Zones in the Ion Source
152

B.  Hot Filament Quasi‐BIRD
153

C.  Laser IRMPD
154

D.  Conclusion
154

References
155

Blackbody infrared radiative dissociation (BIRD) describes the observation of ion‐dissociation reactions at essentially zero pressure by the ambient blackbody radiation field, which is usually studied in the ion‐trapping ion cyclotron resonance (ICR) mass spectrometer. A brief summary of the historical context and evolution is provided. Focussing on the quantitative observation of the temperature dependence of BIRD rates, methods are developed for connecting BIRD observations with activation parameters and dissociation thermochemistry. Three regimes are differentiated and described, comprising large molecules, small molecules, and intermediate‐sized molecules. The different approaches to interpreting BIRD kinetics in those three regimes are discussed. In less than a decade since its inception, this approach to studying gas‐phase ions has spread over a wide variety of applications, which are surveyed. Some major areas of activity are: the characterization of solvent–molecule detachment from solvated ions; dissociation reactions of biomolecules (polypeptides, oligonucleotides, complexes involving polysaccharides) and the structural information to be deduced from them; and dissociations of proton‐bound and metal–ion‐containing complexes. Studies of blackbody‐radiation‐driven evaporation of water molecules from large water‐cluster ions are surveyed briefly. Several techniques related to BIRD are noted, including collisional dissociation in the FT‐ICR ion trap; high‐pressure thermal dissociation in quadrupole ion traps and in heated inlet capillary regions; hot‐filament‐assisted dissociation; and infrared multiphoton dissociation (IRMPD). © 2003 Wiley Periodicals, Inc., Mass Spec Rev 23:127–158, 2004.