Vertical Absorption Research Articles

CCSD‐PCM Excited State Energy Gradients with the Linear Response Singles Approximation to Study the Photochemistry of Molecules in Solution

AbstractWe present the theory and the implementation for the excited state energy gradients with respect to nuclear displacements for the linear response coupled cluster with single and double excitations (LR‐CCSD) combined with the polarizable continuum model of solvation within the LR formalism and the singles approximation (LR‐PCM‐PTES). This approach allows the exploration of the excited state potential energy surface of solvated molecules for the evaluation of minima and other stationary points, at a computational cost virtually identical to that of gas‐phase LR‐CCSD. The method is applied to the evaluation of vertical absorption and emission energies of 4‐(N,N)‐dimethyl‐aminobenzonitrile (DMABN) in gas phase, cyclohexane, and acetonitrile solutions. The method is able to find the minima for the locally excited and charge transfer states, which are responsible for the dual‐fluorescence of this compound. At the same time, some limitations of the LR and state specific (SS) formalisms for excited state solvation, which suffer from under or overestimation of the solvent effect in excited states, are discussed.

Cross-Comparisons between Experiment, TD-DFT, CC, and ADC for Transition Energies.

Considering 41 electronic transitions in small- and medium-sized organic molecules, we benchmark the performances of 36 hybrid functionals within time-dependent density-functional theory (TD-DFT) and nine wave function theory (WFT) methods [CCSDT, CC3, CCSDT-3, CCSDR(3), CCSD, CC2, ADC(3), ADC(2), and SOS-ADC(2)]. Compared to highly accurate experimental 0-0 energies, it turns out that all coupled cluster (CC) approaches that include contributions from the triples [i.e., CCSDT, CC3, CCSDT-3 and CCSDR(3)] deliver a root-mean-square error (RMSE) smaller than or equal to 0.05 eV. The remaining WFT methods [i.e., CCSD, CC2, ADC(3), ADC(2), and SOS-ADC(2)] yield larger deviations with RMSE lying between 0.11 and 0.27 eV. Irrespective of the exchange-correlation functional, TD-DFT yields larger deviations (RMSE ⩾ 0.30 eV). For vertical transitions without clear experimental equivalents (such as vertical absorption and fluorescence), a comparison between TD-DFT and CC3 provides a globally unchanged ranking of the various functionals. However, the errors on emission energies tend to be larger than on absorption energies, hinting that studying the latter property is not sufficient to gain a complete view of TD-DFT's performances. Finally, by cross-comparisons between TD-DFT and WFT, we observe that the WFT method selected as reference significantly impacts the conclusions regarding the overall accuracy of a given exchange-correlation functional. For example, for vertical absorption energies, the "best" functional is TPSSh (RMSE = 0.29 eV) based on CC3 reference energies, while LC-ωPBE (RMSE = 0.12 eV) is superior to the other functionals when one considers ADC(3) as the reference method.

Enhancement of responsivity and speed in waveguide Ge/Si avalanche photodiode with separate vertical Ge absorption, lateral Si charge and multiplication configuration

Waveguide-coupled Ge/Si separate absorption, charge and multiplication avalanche photodiodes (SACM APDs) have shown significant potential as high-sensitivity, low-noise, and high-speed photo-detection for optical communications. Here we present a nanoscale single-mode waveguide-integrated vertical Ge absorption, lateral Si charge and single multiplication configuration for a waveguide Ge/Si SACM APD. This device can achieve 90% absorption at 1550 nm wavelengths with a 10 μm-long Ge layer. The device exhibits a seven times reduction in device length compared to conventional waveguide structures and a 29% increase compared to multi-mode interference coupling. Meanwhile, a 3-dB bandwidth can achieve 47 GHz, which is five times higher than the conventional vertical Ge absorption, lateral Si charge and multiplication devices.

Molecular structure and electronic properties of substituted tetrabenzocoronenes: DFT and TD‐DFT investigations

Abstract1,2:3,4:7,8:9,10‐Tetrabenzocoronene (TBC) is a highly π‐conjugated polycyclic aromatic hydrocarbon (PAH) with an intriguing nonplanar, twisted molecular shape featuring two [4]helicene subunits on the opposite sides of the molecule. In this study, we examined the electronic substituent effects on the molecular properties of a series of TBC derivatives by density functional theory (DFT) and time‐dependent DFT (TD‐DFT) computational analysis at the B3LYP/6‐31G(d) and TD‐B3LYP/6‐311 + G(d,p) levels. The equilibrium geometries for the stable conformers of the TBC derivatives in the ground singlet state (So) and related transition states were optimized to obtain the energy barriers associated with the interconversion among these conformers. Variations of aromatic character for these compounds were evaluated by nucleus‐independent chemical shift (NICS) calculations, while the frontier molecular orbital (FMO) energies and the vertical electronic absorption and emission energies were calculated. The calculated absorption and emission spectra of these TBC derivatives show good correlations with the Hammett substituent constant (σ). Overall, our study has demonstrated that the attachment of electron‐donating/withdrawing substituents to the edges of TBC can exert significant effects on the structural, electronic, and photophysical properties. Understanding of the substitution effects on TBC provides valuable insight for the design and development of novel PAH‐based organic electronic materials and devices.

PMD35 POTENTIAL COST SAVINGS IN TREATMENT OF CHRONIC WOUNDS WITH FIRST WOUND BED CONFORMING WOUND DRESSING

Bioburden in the dead space between the wound dressing (WD) and the wound bed compromises faster wound healing and is associated with economic burden. This study assessed the potential of reduced wound filler (WF) consumption through using the first Wound Bed Conforming (WBC) WD. A budget impact model was developed based on in-vitro properties of vertical absorption. A US study (n=312,744) estimates that 99.9% of venous leg ulcers (VLU) and 99% of diabetic foot ulcers (DFU) are less than 2 cm in depth. A UK study (n=4,772) recorded that 2.4% of the VLUs and 14.4% DFUs are undermined in which case a WBC WD would not be capable of replacing a WF. Wound data from Germany (n=1,009) suggests that 37% of the VLUs and 50% of the DFUs that are not undermined nor deeper than 2 cm are superficial and does not require a WF. The rate of complicated filler removal at dressing change was estimated to be 1 in 4 adding on 5 minutes to the dressing change time. This analysis includes both Medicare payment levels as well as commercial reported hospital payment levels (GHX). When switching from a traditional WD treatment regimen to a WBC WD regimen WF utilization decreases from 64% to 3% in VLUs and from 58% to 15% in DFUs. This corresponds to product cost reductions of 18%-48% depending on product cost perspective and wound type. Including the time spend on complicated filler removal the monthly dressing change costs are reduced by $38-131 per wound. Sensitivity analysis indicates that results are robust. This model suggests that application of WBC WDs in VLUs and DFUs would save 18-73% of the wound dressing change costs depending on a product cost perspective only or also including time spend.

MoS2 photodetectors integrated with photonic circuits

In recent years, two-dimensional materials have risen as an attractive platform for integrated optoelectronics, due to their atomic scale thickness, favorable electrical, mechanical, and optical properties. In particular, graphene has been exploited as an ultrafast light modulator and photodetector, operating at telecommunication wavelengths. However, materials with larger bandgaps are required for light detection in the visible range of the spectrum, with wide applications in space communication, industrial quality controls, light sensing, etc. Even though TMDC-based light emitting and detecting devices in the visible spectrum have already been realized, efficient light absorption and photocurrent generation on integrated devices has not been achieved yet. Here, we demonstrate the integration of an ultrasensitive MoS2 photodetector with a silicon nitride photonic circuit. In contrast to the limited vertical light absorption, we observe near-unity lateral absorption, which results in even higher responsivity. By fabricating an alternative device where the MoS2 semiconducting channel is combined with a hexagonal boron nitride (h-BN) substrate, we significantly improve the speed of the photodetector. Low power operation is further achieved in a third device with graphene local gates. These results pave the way for future TMDC-based integrated optoelectronic devices.

Understanding UV-Vis Spectra of Halogenated Tetraazaperopyrenes (TAPPs): A Computational Study.

The UV-vis absorption and emission spectra of halogenated tetraazaperopyrenes (TAPPs) have been investigated employing second-order approximate coupled cluster (CC2) and (time-dependent) density functional theory (DFT). We have found that the qualitative estimates of (vertical) absorption and excitation energies are possible within a single particle picture based on frontier orbitals, but the single particle picture is not sufficient to achieve quantitative accuracy. Going from the single-particle picture to the many-particle picture improves the agreement with experimental results, but still no satisfying correlation of theory and experiment is obtained. The comparison of CC2- and DFT-based methods reveals that deviations from the experimental results cannot be explained by deficiencies of the electronic-structure methods but rather stem from neglecting vibrational effects. An agreement of theoretical results and experimental spectra is found for adiabatic excitation energies, which are given as energy differences of vibronic states, which are directly accessible using both theoretical and experimental methods. The most pronounced vibronic influence is found for the Stokes shifts, which are significantly overestimated by computing the vertical electronic transitions only. Based on the vibronic contributions, the small Stokes shift of the TAPP compounds can be explained by the temperature dependence of the vibrationally resolved UV-vis spectra.

Accurate Prediction for Dynamic Hybrid Local and Charge Transfer Excited States from Optimally Tuned Range-Separated Density Functionals

Fine regulation of excited-state characteristics of organic molecules plays a vital role in the rational design of novel optoelectronic materials. Recently, the fluorescent emitters with a hybridized local and charge transfer (HLCT)-excited state have attracted significant interest in developing high-efficiency organic light-emitting diodes. The HLCT state generally consists of a mixture of local excitation and charge transfer (CT) characters that are known to be sensitive to molecular configuration and surrounding environment. Thus, both qualitative and quantitative characterizations of “dynamic” HLCT states remain challenging from a theoretical perspective. In this work, a series of donor–acceptor (D–A) molecules with HLCT excited-state characters were theoretically studied using density functional theory (DFT) and time-dependent DFT. Successful prediction of both vertical absorption and emission excitation energies (EVA and EVE) of the lowest singlet excited state (S1) is demonstrated when using the op...

Hückel Molecular Orbital Quantities of {X,Y}-Cyclacene Graphs Under Next-Nearest-Neighbour Approximations in Analytical Forms

Abstract Hückel molecular orbital (HMO) quantities, viz., electron densities, charge densities, bond orders, free valences, total π-electron energies and highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO–LUMO) or band gaps of {X,Y}-cyclacene graphs under next-nearest-neighbour (nnn) approximations are expressed in analytical forms within a certain range of nnn approximation parameter (m). The critical values of m for {X,Y}-cyclacenes with varying X (=C, N, B) and Y (=C, N, B) are calculated. For {X,X}-cyclacenes with a π-electron on each atom, all HMO quantities except total π-electron energies for a given value of m are found to be independent of X. The cyclic dimer (CD) is constructed in obtaining the eigenvalues corresponding to the singular points of the density of states (DOS) of such {X,Y}-cyclacene. Although the HOMO–LUMO gap of the CD differs from that of the cyclacene with a large number of repeating units (i.e. n ⟶ ∞) but becomes the same for m = 0. The analytical expressions can be used for facile computer programming in obtaining the HMO quantities. Such nnn interaction approximations actually release, to some extent, the strain that results in due to the geometrical structures of such cyclacenes, which is evident from the plots of strain energy per segment vs. contribution of such interactions on the total π-electron energy, where the slopes decrease with an increase in m. The vertical absorption energy difference for singlet-triplet states bears excellent linear correlation with the HOMO–LUMO gaps for a certain m value (m = 0.3) in the case of an even n, but for an odd n, such energy difference remains invariant.

Large contrast in the vertical distribution of aerosol optical properties and radiative effects across the Indo-Gangetic Plain during the SWAAMI–RAWEX campaign

Abstract. Measurements of the vertical profiles of the optical properties (namely the extinction coefficient and scattering and absorption coefficients respectively σext ∕ σscat ∕ σabs) of aerosols have been made across the Indo-Gangetic Plain (IGP) using an instrumented aircraft operated from three base stations – Jodhpur (JDR), representing the semi-arid western IGP; Varanasi (VNS), the central IGP characterized by significant anthropogenic activities; and the industrialized coastal location in the eastern end of the IGP (Bhubaneswar, BBR) – just prior to the onset of the Indian summer monsoon. The vertical profiles depicted region-specific absorption characteristics, while the scattering characteristics remained fairly uniform across the region, leading to a west–east gradient in the vertical structure of single-scattering albedo (SSA). Integrated from near the ground to 3 km, the highest absorption coefficient and hence the lowest SSA occurred in the central IGP (Varanasi). Size distribution, inferred from the spectral variation of the scattering coefficient, showed a gradual shift from coarse-particle dominance in the western IGP to strong accumulation dominance in the eastern coast with the central IGP coming in between, arising from a change in the aerosol type from a predominantly natural (dust and sea salt) type in the western IGP to a highly anthropogenic type (industrial emissions, fossil fuel and biomass combustion) in the eastern IGP, with the central IGP exhibiting a mixture of both. Aerosol-induced short-wave radiative forcing, estimated using altitude-resolved SSA information, revealed significant atmospheric warming in the central IGP, while a top-of-atmosphere cooling is seen, in general, in the IGP. Atmospheric heating rate profiles, estimated using altitude-resolved SSA and column-averaged SSA, revealed considerable underestimation in the latter case, emphasizing the importance and necessity of having altitude-resolved SSA information as against a single value for the entire column.

Synthesis of applicable hydrogel corn silk/ZnO nanocomposites on polyester fabric with antimicrobial properties and low cytotoxicity

Corn silk as a clean and cheap agricultural waste with protein and cellulosic structure and traditionally usages was applied on polyester for the first time to increase the cell viability of zinc oxide on polyester fabric creating good hydrogel properties. The corn silk was first dried under sunlight, powdered and dispersed into the homogeneous solution using sodium hydroxide/urea at boil. Zinc acetate and a cationic surfactant along with the polyester fabric were placed in the alkali solution with or without corn silk at boil for 1 h. The samples were characterized by SEM images, EDX, FTIR spectroscopy and XRD. The vertical wicking, water absorption and self-cleaning activities of the treated fabrics were also investigated. The synthesized ZnO without corn silk was presented nanoplate and spherical shape nanoparticles however in presence of corn silk only the spherical shape nanoparticles were formed. Excellent antimicrobial properties against Escherichia coli, Staphylococcus aureus and Candida albicans and cell viability on the human cells were obtained on the fabric conataining corn silk/zinc oxide nanocomposites close to 100 and 87%, respectively. Finally, application of corn silk along with synthesis of ZnO nanoparticles introduced a novel polyester fabric with antimicrobial, highly hydrophilic, self-cleaning properties having low cytotoxicity.

Engineering and design of simple models from dye-sensitive of solar cells and photovoltaic cells applications: Theoretical study

In this study, the optimization geometric and optoelectronic properties of new structures that based on quater[1,3,4]thiadiazole and benzothiophene were calculated by using density functional theory (DFT) and time-dependent (TDDFT) at B3LYP and the 6-31G(d) basis set. The total energy, orbital (HOMO, LUMO) distributions, the energy gaps, the maximum open circuit voltage, maximum wavelength absorption, vertical absorption energies, and oscillator strengths have been investigated and discussed. We studied and discussed effect the donor group substituents (COH, and CP) and the acceptor group substituents (Br, OH, Cl, F, and CN) on optimization geometric, electronic properties, and optical properties the molecules, we observed that the donor group substituents lead to decrease energy gap and the acceptor group substituents lead to increase energy gap. These changes give alteration of maximum wavelengths absorption from 453.1 to 559.9 nm. Therefore, these compounds have major absorption bands inside the solar spectrum, to give a present better performance for the solar cells and photovoltaic devices.

Theoretical Study of the Electronic and Optical Properties to Design Dye-Sensitivity for Using in Solar Cell Device

In this work, the structural and optoelectronic properties of phenanthrene-1,3,4-thaidiazoles oligomers were calculated using density functional theory (DFT) at B3LYP/6-31G(d) basis set level, to evaluate their possible application as organic semiconductor materials in photovoltaic and solar cell devices. For this reason, the energy gaps, frontier orbital (HOMO, and LUMO) distributions, total energies, Fermi level energies, work functions and maximum wavelength absorption, vertical absorption energies, and oscillator strengths have been investigated and discussed. The structures of phenanthrene-1,3,4-thiadiazoles oligomers are expanded from 1 to 10 thiadiazole monomeric units, to examine the increase of thiadiazole monomeric units on the optoelectronic properties. We observed that increased the number of monomeric units lead to significantly enhance the optoelectronic properties, which caused to decrease the gap energy from 3.69 eV in the structure with one thiadiazole ring just to 2.36 eV with 10 units. These changes give the shift of maximum absorption wavelengths from 376 to 578 nm. Consequently, these molecules have main absorption bands within the solar spectrum, to give the best performance for photovoltaic and organic solar cells devices.

A new elastomeric-sliding seismic isolation system

A new seismic isolation system is introduced in this study that utilizes a combination of confined rubber for vertical loading and sliding rings for energy absorption. In this new system, a central elastomeric core is contained between the steel sliding rings. In laboratory testing of the proposed system, it was shown that the steel rings maintained the required vertical stiffness of the system by controlling the lateral deformation of the rubber core. In the lateral motion, the steel rings dissipated energy by sliding on each other under a friction force limited by their small share of the gravity loads. The advantages of the proposed system as compared with the conventional laminated-rubber bearing include increased vertical stiffness and energy absorption capacity as well as ease of manufacturing at a lowered cost.

Solvent effects for vertical absorption and emission processes in solution using a self-consistent state specific method based on constrained equilibrium thermodynamics.

A self-consistent state specific (SS) method in the framework of TDDFT is presented to account for solvent effects on absorption and emission processes for molecules in solution. In these processes, the initial state is an equilibrium state, while the polarization of the solvent is in nonequilibrium with the electron density of the solute in the final state. Nonequilibrium solvation free energy is calculated based on a novel nonequilibrium solvation model with constrained equilibrium manipulation. The bulk solvent effects are considered using the polarizable continuum method (PCM), where the solvent-solute interaction is described with a reaction field. Molecular orbitals and orbital energies in the presence of the reaction field corresponding to the excited state are employed and the response of the solvent is not included in the TDDFT calculations. A self-consistent procedure is designed to obtain the excited state reaction field. The equations based on this new nonequilibrium solvation model in the framework of the self-consistent SS-PCM/TDDFT method for calculation of vertical absorption and emission energies are presented and implemented in the Q-Chem package. Vertical absorption and emission energies for several small molecules in solution using the newly developed code are calculated and compared with available experimental data and the results of other theoretical studies. Solvent shifts of absorption and emission energies are reasonably reproduced with this approach. The new model is a promising approach to study nonequilibrium absorption and emission processes in solution.

Speed-Up of the Excited-State Benchmarking: Double-Hybrid Density Functionals as Test Cases.

The EX6-0, EX7-0, and EX7-1 representative benchmark sets are developed for the fast evaluation of the performance of a density functional, or more generally of a computational protocol, in modeling low-lying valence singlet-singlet excitation energies of organic dyes within the range of 1.5 to 4.5 eV. All sets share the advantage of being small (a maximum of 7 molecules) but providing statistical errors representative of larger and extended databases. To that extent, the EX7-1 benchmark set goes a step further and is composed of systems as small as possible in order to alleviate the associated computational cost. The reliability of all the sets is assessed through the benchmarking of 15 modern double-hybrid density functionals. The investigation shows not only that the 3 benchmark sets provide close error metrics for each density functional but also that when taking advantage of the Resolution-of-the-Identity and a balanced triple-ζ basis set (e.g., def2-TZVP), double hybrids overperform the "popular" hybrids in modeling vertical absorption, emission, and adiabatic energies.

Continuous photosynthetic abatement of CO2 and volatile organic compounds from exhaust gas coupled to wastewater treatment: Evaluation of tubular algal-bacterial photobioreactor

The continuous abatement of CO2 and toluene from the exhaust gas by an indigenous microalgal-bacterial consortium was investigated in a pilot tubular photobioreactor interconnected to an absorption column using diluted centrate in seawater as a free nutrient source. The removal efficiency of CO2 and toluene was maximised in the vertical absorption column by identifying an optimum liquid to gas (L/G) ratio of 15. The photobioreactor supported steady-state nitrogen and phosphorus removals of 91±2% and 95±4% using 15% diluted centrate at 14 and 7 d of hydraulic retention time (HRT), respectively. A decrease in the removal efficiencies of nitrogen (36±5%) and phosphorus (58±10%) was recorded when using 30% diluted centrate at 7 d of HRT. The volumetric biomass productivities obtained at an HRT of 7 d accounted for 42±11 and 80±3mg TSS L−1 d−1 using 15 and 30% centrate, respectively. Stable CO2 (76±7%) and toluene removals (89±5%) were achieved at an L/G ratio of 15 regardless of the HRT or centrate dilution. Hence, this study demonstrated the potential of algal-bacterial systems for the continuous removal of CO2 and volatile organic compounds from exhaust gas coupled with the simultaneous treatment of centrate.

Influence of vibronic contribution on light harvesting efficiency of NKX-2587 derivatives with oligothiophene as π-conjugated linker

Based on the NKX-2587 molecule we designed ten sensitizers with 1–10 thiophene moieties to investigate how the number of thiophene unit in the spacer influences the absorption spectra of sensitizer in dye sensitized solar cells (DSSCs). The parameters of short-circuit current density (Jsc), open circuit voltage (Voc), the light harvesting efficiency (LHE), injection driving force (∆Ginject), and transferred electron number (nc), were calculated and discussed in detail. Results indicated that the increasing of thiophene units makes for the enhancement of oscillator strengths (f), although the red shift of vertical electronic absorption spectra is small. For the designed sensitizers with 1–5 thiophene units, their ΔGinject and nc raise gradually with the increasing of thiophene number. However, for those sensitizers with 6–10 thiophene units, the ΔGinject and nc decrease continuously with the increasing of thiophene units. In order to study how the oligothiophene as π-conjugated linker affects light harvesting efficiency of DSSCs, the vibrationally resolved electronic spectra of five metal-free NKX-2587 derivatives with 1–5 thiophene units were simulated within the Franck-Condon approximation including the Herzberg-Teller and Duschinsky effects. The present theoretical results provided helpful guidance for understanding the sources of spectral intensities of dye molecules, and a valuable method for rational design of new molecules to improve the energy conversion efficiency (η) of DSSCs.

The MERRA-2 Aerosol Reanalysis, 1980 Onward. Part I: System Description and Data Assimilation Evaluation

The Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) updates NASA's previous satellite era (1980 - onward) reanalysis system to include additional observations and improvements to the Goddard Earth Observing System, Version 5 (GEOS-5) Earth system model. As a major step towards a full Integrated Earth Systems Analysis (IESA), in addition to meteorological observations, MERRA-2 now includes assimilation of aerosol optical depth (AOD) from various ground- and space-based remote sensing platforms. Here, in the first of a pair of studies, we document the MERRA-2 aerosol assimilation, including a description of the prognostic model (GEOS-5 coupled to the GOCART aerosol module), aerosol emissions, and the quality control of ingested observations. We provide initial validation and evaluation of the analyzed AOD fields using independent observations from ground, aircraft, and shipborne instruments. We demonstrate the positive impact of the AOD assimilation on simulated aerosols by comparing MERRA-2 aerosol fields to an identical control simulation that does not include AOD assimilation. Having shown the AOD evaluation, we take a first look at aerosol-climate interactions by examining the shortwave, clear-sky aerosol direct radiative effect. In our companion paper, we evaluate and validate available MERRA-2 aerosol properties not directly impacted by the AOD assimilation (e.g. aerosol vertical distribution and absorption). Importantly, while highlighting the skill of the MERRA-2 aerosol assimilation products, both studies point out caveats that must be considered when using this new reanalysis product for future studies of aerosols and their interactions with weather and climate.

Fluorescein effect on the vase life of calla (Zantedeschia aethiopica (L.) K. Spreng.) inflorescences

Calla (Zantedeschia aethiopica (L.) K. Spreng), is a cut flower which had obtained importance in recent years, but postharvest handling is limited. Thus, in order to know the fluorescein concentration effect and pH of pulse solution on inflorescences calla postharvest, were evaluated in Teotitlan de Flores Magon, Oaxaca-Mexico, four fluorescein concentrations (0, 20, 40 and 60 %, respectively) and two pH levels (acid and alkaline) in a completely randomized design with factorial arrangement, having a total of 24 experimental units, which was established by vase life and calla inflorescence with white spathe color, immersed in a fluorescein solution adjusted as appropriate at acidic or alkaline pH, where response variables were as follows: vase life, water consumption, stem diameter, absorption fluorescein stem base and fluorescein vertical absorption by floral scape. Results indicates the increased vase life is achieved at alkaline pH by fluorescein addition of 20, 40 and 60 %, respectively. Likewise, the higher water consumption is achieved at this pH. From this research, we can conclude fluorescein can affect the calla physiology for increasing vase life.