Simultaneous Two-Photon Absorption to Gerade Excited Singlet States of Diphenylacetylene and Diphenylbutadiyne Using Optical-Probing Photoacoustic Spectroscopy

Abstract

Simultaneous two-photon absorption to one-photon forbidden electronically excited states of diphenylacetylene (DPA) and diphenylbutadiyne (DPB) was investigated by means of highly sensitive optical-probing photoacoustic spectroscopy. The incident laser power dependencies on photoacoustic signal intensity indicate that the signals are dominated by the two-photon absorption regime. Two-photon absorption is responsible for transitions to gerade excited states based on the selection rule. The two-photon absorption bands observed in the heat action spectra were assigned with the aid of quantum chemical calculations. The relative magnitude of the two-photon absorption cross sections of DPA and DPB was estimated, and the larger two-photon absorption cross section of DPB was related to the resonance effect with the red-shifted one-photon allowed 1(1)B1u ← 1(1)Ag transition of DPB.

Simultaneous Two-Photon Absorption of the Thioguanosine Analogue 2′,3′,5′-Tri-O-acetyl-6,8-dithioguanosine with Its Potential Application to Photodynamic Therapy

“…The experimental setup for OPPAS measurement has been described elsewhere. 17,18 An optical parametric oscillator (OPO) laser (Continuum, Panther EX OPO; linearly polarized, pulse width 3-5 ns, line width < 6 cm -1 ) pumped by third harmonic of a Nd 3+ :YAG laser (Continuum, Surelite Ⅱ; pulse width 4-6 ns, repetition rate 10 Hz) and a He-Ne laser (LASOS,…”

“…The experimental setup for OPPAS measurement has been described elsewhere. , An optical parametric oscillator (OPO) laser (Continuum, Panther EX OPO; linearly polarized, pulse width 3–5 ns, line width <6 cm –1 ) pumped by third harmonic of a Nd 3+ :YAG laser (Continuum, Surelite II; pulse width 4–6 ns, repetition rate 10 Hz) and a He–Ne laser (LASOS, LGK 7634; ≥2 mW, cw 632.8 nm) were used as the excitation and probe sources, respectively. The excitation laser power was attenuated with a variable neutral density filter to obtain the incident laser power dependence on the OPPAS signal.…”

“…In this article, we investigated the two-photon excitation wavelength and the two-photon absorption cross-section σ (2) of taDTGuo by optical-probing photoacoustic spectroscopy (OPPAS), − a PAS technique for detecting transient angular deflection of the probe beam. We also simulated two-photon absorption spectra of thioguanine derivatives using the quantum chemical calculation to better understand the nature of higher two-photon absorption cross-sections for thioguanosines.…”

“…(OPPAS), [16][17][18] a PAS technique detecting a transient angular deflection of the probe beam. We also simulated two-photon absorption spectra of thioguanine derivatives by using the quantum chemical calculation to better understand the nature of higher two-photon absorption cross sections for thioguanosines.…”

Fluorinated tolane-based fluorophores bearing a branched flexible unit with aggregation-induced emission enhancement characteristics

“…3,4 Additionally, small-molecule organic light-emitting diodes (OLEDs) have attracted enormous attention because of their low-cost fabrication and production; they are applicable to a wide range of display devices, such as flat-panel displays and flexible displays. 5 Tolanes, which have a structure of two aromatic rings connected by alkyne moieties, have been recognized as promising candidates for small-molecule fluorophores owing to their broad applications as two-photon absorbers, 6 liquid crystals, 7 and organic semiconductors. 8 However, it has been reported that tolanes are not emissive at room temperature because the excitons generated after excitation immediately undergo internal conversion from fluorescent pp* to dark ps* excited states with a trans-bend molecular shape.…”