A combined theoretical and experimental study of the ultrafast photophysics of Rhodamine B

Abstract

The ultrafast dynamics of zwitterionic and cationic Rhodamine B in ethanol have been investigated using TDDFT calculations and ultrafast transient absorption spectroscopy. The calculations show that the zwitterionic form exhibits an electronically excited dark state which could potentially quench the initially photoexcited state, while in the case of cationic form the lowest excited lying dark state is outside the energy region of interest and cannot explain its quenching. Due to similarities in the relaxation dynamics of the two molecules, it is suggested that the electronically excited dark state may not play such an important role in the quenching process of this dye as previously proposed. Experimental evidence presented suggests that a quenching mechanism is active on the picosecond timescale for both forms of Rhodamine B.

A Fast Transient Absorption Study of Co(AcAc)3

“…Measurements were taken at the magic angle between the linear polarization vectors of pump and probe radiation. Further details of the experimental set-up can be found in previous publications (Catone et al, 2018; Fratoddi et al, 2018).…”

“…TDDFT and the chosen basis set are a good compromise between accuracy and computer time consuming for these complexes. TDDFT with B3LYP has been successfully used in the literature to characterize the electronic structure in similar calculations (Savarese et al, 2012, 2014; Catone et al, 2018).…”

Photocatalyzed electron exchange between organic chromophores and hematite nanoparticles and the role of solid-state charge transport

“…52 Although RhB is not commonly found in geochemical environments, we utilized it as a probe organic because it is well characterized experimentally and theoretically for its transient absorption and excited-state dynamics behavior. 53–60 Because it is chemically stable and undergoes highly reversible photoexcitation under suitable conditions, 55,57,59,61–63 RhB enabled us to focus on the dye relaxation lifetime as a proxy for interfacial electron transfer processes without the interference of simultaneous photodegradation. Furthermore, the pH-dependent speciation of RhB is well known and compatible with the pH-dependent electrostatics of hematite surfaces over a wide pH range, enabling more insight into the role of interfacial electrostatics than in prior work.…”

Photoassisted degradation of rhodamine B using poly(ε‐caprolactone) based nanocomposites: Mechanistic and kinetic features

“…Evaluation of the photocatalytic efficiency of PCl‐C10A is supplemented by a possible mechanism for degradation along with in‐depth analysis of the cytotoxicity of the end products and correlating it with preliminary theoretical study on the initial state gas phase oxidative degradation mechanism for cationic form of RhB, by density functional theory (DFT) 35–38 …”