@article{LeupoldTeuchnerEhlertetal.2006,
  author    = {Leupold, Dieter and Teuchner, Klaus and Ehlert, J{\"u}rgen and Irrgang, Klaus-Dieter and Renger, Gernot and Lokstein, Heiko},
  title     = {Stepwise two-photon excited fluorescence from higher excited states of chlorophylls in photosynthetic antenna complexes},
  issn      = {0021-9258},
  doi       = {10.1074/jbc.M600080200},
  year      = {2006},
  language  = {en}
}
@article{LoksteinHoextermannLeupoldetal.2009,
  author    = {Lokstein, Heiko and Hoextermann, Ekkehard and Leupold, Dieter and Garab, Gyoezoe and Renger, Gernot},
  title     = {A tribute : Professor Dr. Paul Hoffmann (March 28, 1931-July 10, 2008), a scientist with a great collaborative spirit},
  issn      = {0166-8595},
  doi       = {10.1007/s11120-009-9414-6},
  year      = {2009},
  language  = {en}
}
@article{KrikunovaLoksteinLeupoldetal.2006,
  author    = {Krikunova, Maria and Lokstein, Heiko and Leupold, Dieter and Hiller, Roger G. and Voigt, B.},
  title     = {Pigment-pigment interactions in PCP of Amphidinium carterae investigated by nonlinear polarization spectroscopy in the frequency domain},
  year      = {2006},
  abstract  = {Peridinin-chlorophyll a-protein (PCP) is a unique antenna complex in dinoflagellates that employs peridinin (a carotenoid) as its main light-harvesting pigment. Strong excitonic interactions between peridinins, as well as between peridinins and chlorophylls (Chls) a, can be expected from the short intermolecular distances revealed by the crystal structure. Different experimental approaches of nonlinear polarization spectroscopy in the frequency domain (NLPF) were used to investigate the various interactions between pigments in PCP of Amphidinium carterae at room temperature. Lineshapes of NLPF spectra indicate strong excitonic interactions between the peridinin's optically allowed S-2 (1Bu(+)) states. A comprehensive subband analysis of the distinct NLPF spectral substructure in the peridinin region allows us to assign peridinin subbands to the two Chls a in PCP having different S-1-state lifetimes. Peridinin subbands at 487, 501, and 535 nm were assigned to the longer-lived Chl, whereas a peridinin subband peaking at 515 nm was detected in both clusters. Certain peridinin(s), obviously corresponding to the subband centered at 487 nm, show(s) specific (possibly Coulombic?) interaction between the optically dark S-1(2A(g)(-)) and/or intramolecular charge- transfer (ICT) state and S-1 of Chl a. The NLPF spectrum, hence, indicates that this peridinin state is approximately isoenergetic or slightly above S-1 of Chl a. A global subband analysis of absorption and NLPF spectra reveals that the Chl a Q(y)-band consists of two subbands ( peaking at 669 and 675 nm and having different lifetimes), confirmed by NLPF spectra recorded at high pump intensities. At the highest applied pump intensities an additional band centered at <= 660 nm appears, suggesting-together with the above results-an assignment to a low-dipole moment S-0-> S-1/ICT transition of peridinin},
  language  = {en}
}
@article{LeupoldLoksteinScheer2006,
  author    = {Leupold, Dieter and Lokstein, Heiko and Scheer, Hugo},
  title     = {Excitation energy transfer between (bacterio)chlorophylls : the role of excitonic coupling},
  year      = {2006},
  language  = {en}
}
@article{SchneiderTeuchnerLeupold2005,
  author    = {Schneider, M. and Teuchner, Klaus and Leupold, Dieter},
  title     = {Two-photon fluorescence of ocular melanomas. Studies on a new diagnostic method},
  issn      = {0941-293X},
  year      = {2005},
  abstract  = {Choroidal melanoma is the most frequent form of primary neoplasia among malignant ocular tumors. Since it is presumed that metastasis often occurs before the primary tumor is first diagnosed, early detection is exigent. The aim of the studies described in this report was to develop an objective, noninvasive method for the diagnosis of choroidal melanoma. The underlying new principle of fluorescence excitation is presented. This is based on the observation that melanin, due to its unique absorption characteristics, is selectively excited into fluorescence via stepwise absorption of two photons of a femtosecond laser emitting at 800 nm. In the experiment described, the fluorescence of excised tissue from healthy choroidal pigment epithelium was compared to that of excised choroidal melanoma. The fluorescence of choroidal melanomas exhibited a more reddish appearance and less intensity than that of healthy tissue. This implies that the configuration of melanin apparently changes during the process of malignant degeneration. The method described here could thus serve as an evidentiary objective diagnostic technique before initiating treatment for choroidal melanomas},
  language  = {en}
}
@article{LegallStielBecketal.2007,
  author    = {Legall, Herbert and Stiel, Holger and Beck, Michael and Leupold, Dieter and Gruszecki, Wieslaw I. and Lokstein, Heiko},
  title     = {Near edge X-ray absorption fine structure spectroscopy (NEXAFS) of pigment-protein complexes : peridinin- chlorophyll a-protein (PCP) of Amphidinium carterae},
  issn      = {0165-022X},
  doi       = {10.1016/j.jbbm.2006.08.005},
  year      = {2007},
  abstract  = {Peridinin-chlorophyll a protein (PCP) is a unique water soluble antenna complex that employs the carotenoid peridinin as the main light-harvesting pigment. In the present study the near edge X-ray absorption fine structure (NEXAFS) spectrum of PCP was recorded at the carbon Kedge. Additionally, the NEXAFS spectra of the constituent pigments, chlorophyll a and peridinin, were measured. The energies of the lowest unoccupied molecular levels of these pigments appearing in the carbon NEXAFS spectrum were resolved. Individual contributions of the pigments and the protein to the measured NEXAFS spectrum of PCP were determined using a "building block" approach combining NEXAFS spectra of the pigments and the amino acids constituting the PCP apoprotein. The results suggest that absorption changes of the pigments in the carbon near K-edge region can be resolved following excitation using a suitable visible pump laser pulse. Consequently, it may be possible to study excitation energy transfer processes involving "optically dark" states of carotenoids in pigment-protein complexes by soft X-ray probe optical pump double resonance spectroscopy (XODR).},
  language  = {en}
}
@article{GruszeckiStielNiedzwiedzkietal.2005,
  author    = {Gruszecki, Wieslaw I. and Stiel, H. and Niedzwiedzki, Dariusz and Beck, Michael and Milanowska, J. and Lokstein, Heiko and Leupold, Dieter},
  title     = {Towards elucidating the energy of the first excited singlet state of xanthophyll cycle pigments investigated by x-ray absorption spectroscopy},
  year      = {2005},
  language  = {en}
}
@article{BeckStielLeupoldetal.2001,
  author    = {Beck, Michael and Stiel, H. and Leupold, Dieter and Winter, Bernd and Pop, D. and Vogt, U. and Spitz, Christian},
  title     = {Evaluation of the energetic position of the lowest excited singlet state of ß-carotene by NEXAFS and photoemission spectroscopy},
  year      = {2001},
  language  = {en}
}