Conclusions and Outlook
Gas-phase action spectroscopy of porphyrin and heme ions has given a wealth of
data that shed light on the intrinsic electronic properties of these highly important biomolecules. With these data at hand, it is possible to better understand
how a microenvironment such as amino acids or single water molecules perturbs
the electronic structure of a heme buried inside a hydrophobic pocket. Moreover,
the data provide a natural testing ground for future benchmarking of advanced
theoretical calculations on these ions.
There are still many more relevant questions to address. All the data until now
have concentrated on ferric heme, but it would be worthwhile to do similar
35.0
35.5
36.0
36.5
37.0
37.5
38.0
0
20
40
60
80
100
CID decay
2
= 0.87 ms
t
Counts / 100
Time (ms)
1
= 67 s
t
m
Fig. 7.17 From the areas under the decay spectrum associated with each decay (indicated by blue
and green), the branching ratios of photoexcited PP anions can be found. Values of 40 % and 60 %
were found for the fast and slow decays, respectively
Fig. 7.18 Schematic illustration of pump-probe experiments at the ELISA storage ring. Ions are
photoexcited with one laser pulse, and then after a certain number of revolutions in the ring, they
are photoexcited once more by another laser pulse. The time delay between the two laser pulses
corresponds to one or more revolutions in the ring
134
J.A. Wyer and S.B. Nielsen
Gas-phase action spectroscopy of porphyrin and heme ions has given a wealth of
data that shed light on the intrinsic electronic properties of these highly important biomolecules. With these data at hand, it is possible to better understand
how a microenvironment such as amino acids or single water molecules perturbs
the electronic structure of a heme buried inside a hydrophobic pocket. Moreover,
the data provide a natural testing ground for future benchmarking of advanced
theoretical calculations on these ions.
There are still many more relevant questions to address. All the data until now
have concentrated on ferric heme, but it would be worthwhile to do similar
35.0
35.5
36.0
36.5
37.0
37.5
38.0
0
20
40
60
80
100
CID decay
2
= 0.87 ms
t
Counts / 100
Time (ms)
1
= 67 s
t
m
Fig. 7.17 From the areas under the decay spectrum associated with each decay (indicated by blue
and green), the branching ratios of photoexcited PP anions can be found. Values of 40 % and 60 %
were found for the fast and slow decays, respectively
Fig. 7.18 Schematic illustration of pump-probe experiments at the ELISA storage ring. Ions are
photoexcited with one laser pulse, and then after a certain number of revolutions in the ring, they
are photoexcited once more by another laser pulse. The time delay between the two laser pulses
corresponds to one or more revolutions in the ring
134
J.A. Wyer and S.B. Nielsen