understand the dynamical aspects of the excited-state relaxation processes. In Fig. 9.9,
the calculated electronic spectra of the three lowest conformers of TyrH
+ are presented
in comparison with the experimental spectrum taken from the work of Stearns et al.
[18]. The spectra are calculated using the pgopher software [49]. In this figure, the
scale is normalised to the 0–0 transition of conformer A. The absolute transition
energy for conformer A has been calculated to be at 35,345 cm
À1 whereas the
experimental transition origin is 35,083 cm
À1
, i.e., the calculated value is 262 cm
À1
too high (calculation at the ri-cc2/cc-pVDZ level including S 0 and S 1 optimisation as
well as variation of the zero-point energy, performed with the Turbomole package
Fig. 9.7 Photo-excitation spectra of cold protonated tyrosine taken from Stearns et al. [18].
Different isomers are labelled A, B, C, and D. Isomers B and D preferentially give the fragment
at m/z ¼ 107 or 108 (C α -C β bond rupture). Reprinted with permission from [18]. Copyright (2007)
American Chemical Society
Fig. 9.8 Infrared/UV spectra of protonated tyrosine in an ion trap selecting the band origin of
either isomer A or isomer B from the work of Stearns et al. [18]. The most stable isomer is isomer
B. The full sticks are the calculated scaled harmonic vibrations and the dotted sticks are the
unscaled anharmonic ones. Reprinted with permission from [18]. Copyright (2007) American
Chemical Society
9 Excited-State Dynamics of Protonated Aromatic Amino Acids
167
the calculated electronic spectra of the three lowest conformers of TyrH
+ are presented
in comparison with the experimental spectrum taken from the work of Stearns et al.
[18]. The spectra are calculated using the pgopher software [49]. In this figure, the
scale is normalised to the 0–0 transition of conformer A. The absolute transition
energy for conformer A has been calculated to be at 35,345 cm
À1 whereas the
experimental transition origin is 35,083 cm
À1
, i.e., the calculated value is 262 cm
À1
too high (calculation at the ri-cc2/cc-pVDZ level including S 0 and S 1 optimisation as
well as variation of the zero-point energy, performed with the Turbomole package
Fig. 9.7 Photo-excitation spectra of cold protonated tyrosine taken from Stearns et al. [18].
Different isomers are labelled A, B, C, and D. Isomers B and D preferentially give the fragment
at m/z ¼ 107 or 108 (C α -C β bond rupture). Reprinted with permission from [18]. Copyright (2007)
American Chemical Society
Fig. 9.8 Infrared/UV spectra of protonated tyrosine in an ion trap selecting the band origin of
either isomer A or isomer B from the work of Stearns et al. [18]. The most stable isomer is isomer
B. The full sticks are the calculated scaled harmonic vibrations and the dotted sticks are the
unscaled anharmonic ones. Reprinted with permission from [18]. Copyright (2007) American
Chemical Society
9 Excited-State Dynamics of Protonated Aromatic Amino Acids
167