Subpicosecond transient vibrational spectroscopy of heme complex photodissociation

L. Rothberg, T. M. Jedju, R. H. Austin

Research output: Contribution to conferencePaperpeer-review


The authors have developed an apparatus to record transient IR vibrational spectra with 0.5-ps resolution. This technique has been applied to tracking the CO ligand dynamics during photodissociation of carboxyhemoglobin (HbCO) in water solution at room temperature. Transient bleaching of the CO stretching band of HbCO at 1952 cm-1 is observed. The polarization dependence of the bleaching can be used to determine the bond angle between the CO ligand and the heme plane to be 90°±12°. A novel species is observed within the instrumental resolution that has a CO stretching frequency of 2009 cm-1 and a lifetime of 2±1 ps. The authors believe that this is the signature of HbCO in a metastable electronically excited state prior to dissociation. In <5 ps, a second transient is observed with CO absorption at 2132 cm-1. This band is assigned to CO loosely bound in the protein pocket.

Original languageEnglish (US)
Number of pages2
StatePublished - 1989
Externally publishedYes
EventQuantum Electronics and Laser Science Conference - Baltimore, MD, USA
Duration: Apr 24 1989Apr 28 1989


OtherQuantum Electronics and Laser Science Conference
CityBaltimore, MD, USA

All Science Journal Classification (ASJC) codes

  • General Engineering


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