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A study was conducted to investigate the emission properties of nonplanar diprotonated porphyrin, planar porphyrin, and tetraoxaporphyrin dication upon photoexcitation in the [S.sub.2] state at room temperature in solution. Based on the ab initio model calculations, it is proposed that excited states of the [H.sub.4]P.sup.2+][(C[F.sub.3]CO[O.sup.-]).sub.2] complex with charge transfer character are responsible of the increased extension of the [S.sub.2] -> [S.sub.0] spectrum with respect to that of [H.sub.2]P.

Fluorescence and Raman spectra of two representative bridged [14]annulenes, namely 1,6:8,13-ethanediylidene[14]-annulene and 1,6:8,13-propanediylidene[14]annulene are measured. The Raman spectra are measured using several excitation wavelengths in pre- and/or near-resonance conditions with respect to the L(sub a) and B(sub a) states.

The transient spectra of azulene in solution were measured in the spectral region 600-350 nm at room temperature, pumping into the S1 and S2 states with femtosecond pulses and probing with a delayed femtosecond white light continuum. It was found that electronic states, weakly active in the ground-state absorption, occurred with high intensity in the femtosecond transient spectra, particularly in the energy range 36000-44000 cm (super -1) above the ground-state energy.

Vibrational spectra of bridged [14]annulenes with an anthracene perimeter are presented and discussed on the basis of density functional calculations with the B3LYP functional and 6-31G** and cc-pVDZ, basis sets. The Raman spectra are obtained exciting at 647.1 and 1064 nm, that is, in pre- and off-resonance excitation conditions, respectively.

Studies are conducted to investigate the two-photon fluorescence excitation and optoacoustic spectra of red polyDCHD-HS in benzene solution at room temperature in the 1600-750 nm exciting wavelength region (effective tow-photon energy ~1.55-3.31 eV). The current theories of electronic states of pie-conjugated polymers are discussed.

The two-photon fluorescence excitation spectrum of 1,6-methano-[10]annulene which are measured in fluid solution at room temperature between 25 000 and 40 000 cm (super -1) and in rigid solution at 77 and 15 K between 25 000 and 28 000 cm (super -1) are investigated. The applying two-photon polarization results to 1,6-methano-[10]annulene [C (subscript 2v) symmetry], the tensor elements of the strongest totally symmetric S (subscript 0) (right arrow) S1(B1 x b 1 x a1) transition.

Background: MRI has been suggested as a radiation‐free imaging modality to investigate early structural alterations and regional functional impairment in cystic fibrosis (CF) lung disease. Purpose/Hypothesis: To compare functional and morphological MRI changes over the course of the disease to changes in spirometry. Study Type: Longitudinal retrospective study. Population: Twenty patients with CF lung disease (at baseline, age = 16.5 (13.3–20.6) years, forced expiratory volume in 1 second (as % of predicted [%pred]) FEV1 = 71 (59–87) %pred, forced expiratory flow at 25–75% of forced vital capacity FEF25‐75 = 39 (25–63) %pred. Field Strength/Sequence: 1.5T / T2‐weighted HASTE; T2‐weighted TSE‐PROPELLER; T2‐weighted bSSFP; T1‐weighted 3D GRE. Assessment Nonenhanced chest MRI and spirometry were retrospectively collected over a 3‐year period from the initial recruitment visit. Images acquired at end‐inspiration and end‐expiration were registered by software using the optical flow method to measure expiratory‐inspiratory differences in MR signal‐intensity (Δ1H‐MRI). Measures of CF functional impairment were defined from Δ1H‐MRI: Δ1H‐MRI median, Δ1H‐MRI quartile coefficient of variation (QCV), and percent low‐signal‐variation volume (LVV). MR images were also evaluated by three readers using a CF‐specific scoring system. Statistical Tests: Spearman correlation analysis, Spearman rank correlation analysis, linear mixed‐effect model analysis, intraclass correlation coefficient. Results: Functional imaging parameters and total morphological score correlated with all spirometric measures, as did subscores of bronchial wall thickening/bronchiectasis, mucus plugging, and consolidation. Overall, the percent change of Δ1H‐MRI median correlated with the percent change of FEV1 (ΔFEV1, r = 0.41, P < 0.01) and the percent change of FEF25‐75 (ΔFEF25‐75%, r = 0.38, P < 0.01). The percent change of LVV correlated with ΔFEV1 (r = –0.47, P < 0.001) and ΔFEF25‐75 (r = –0.50, P < 0.001). Data Conclusion: These preliminary results suggest that nonenhanced multivolume MRI may provide a feasible tool to regionally map early pulmonary alterations for longitudinal evaluation of CF lung disease, without exposing the patients to ionizing radiation. Level of Evidence: 3T Technical Efficacy Stage: 5 [ABSTRACT FROM AUTHOR]

The studies of the relaxation dynamics of unsubstituted porphyrin ([H.sub.2]P), diprotonated porphyrin ([H.sub.4][P.sup.2+]), and tetraoxaporphyrin dication (TOx[P.sup.2+]) is described. The results provide better understanding of the relaxation dynamics from the lowest [pi][pi]* states of monomer porphyrins for both free bases and metal complexes.

A detailed study was conducted on the stable conformations of the structural and vibrational properties of tetraoxaporphyrin dication and an isoelectronic diprotonated porphyrin. It was indicated that the DFT calculations with high quality basis sets may be reliably applied to molecular systems of medium/large size and give substantial help for an accurate analysis of the vibrational spectra.

The study was conducted to measure the fluorescence spectra of all-trans-retinal as polycrystalline solid and in high concentrated n-hexene solutions at 77 K as a function of the exciting wavelength between 420 and 500 nm that is below the energy of the lowest excited stated of all-trans-retinal. Emmissions from hydrogen-bonded complexes and retinal clusters were observed in solution only from the latter spices in the crystal case.

Optical absorption and optoacoustic spectroscopy is used to measure the high overtone C-H stretching vibrations of anisole and thioanisole in liquid phases. A comparison of the DFT data with the overtone spectra confirmed the occurrence of the methyl C-H symmetric stretching at low wave number in anisole.