Quantum Yield Puns

Journal of the American Chemical SocietyDOI: 10.1021/jacs.1c06094

Don M. Mayder, Christopher M. Tonge, Giang D. Nguyen, Michael V. Tran, Gary Tom, Ghinwa H. Darwish, Rupsa Gupta, Kelsi Lix, Saeid Kamal, W. Russ Algar, Sarah A. Burke, and Zachary M. Hudson

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In the review paper "Photocatalysts for degradation of dyes in industrial effluents: Opportunities and challenges", the authors calculated the quantum yields (molecules per photon) of different photocatalysts (from various published research papers) for dye degradation.

I have tried calculating the quantum yields based on the formulae provided [Quantum yield=Decay rate (molecules per second)/Photon flux (photons per second)] but get different values than those presented in the paper.

Can anyone please guide me step-by-step through the calculation?

Journal of the American Chemical SocietyDOI: 10.1021/jacs.0c13071

Hongchao Yang, Renfu Li, Yejun Zhang, Mengxuan Yu, Zan Wang, Xi Liu, Wenwu You, Datao Tu, Ziqiang Sun, Rong Zhang, Xueyuan Chen, and Qiangbin Wang

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Hi! I've been growing a little over five years now and in that time I've used single ended HPS, DE HPS, and LEC for flowering, all with great results. I typically enjoy yields of 2-3lbs per 1000w light. Some of my friends have made the switch to LED and are hitting similar numbers with half the watts, with beautiful quality buds. However these guys are using $1300 gavita 1700 LEDs, I'm not sure I want to drop that kind of cash on one light so I was wondering anybody had experience running both a high end LED and say a DIY quantum board (the HLG DIY 620watt kit is only $750) or quantum board vs 1000w HPS? How comparable were quality and yield? Any input is appreciated, thanks

Red luminescence in off‐white tris(iodoperchlorophenyl)methane crystals is characterized by a high quantum yield (PLQY 91 %) and color purity. The emission originates from the doublet excited state of the neutral radical defect. TD‐DFT calculations demonstrate that electron‐donating iodine atoms accelerate the radiative transition while the rigid halogen‐bonded matrix suppresses the nonradiative decay.

Abstract

Red luminescence is found in off‐white tris(iodoperchlorophenyl)methane (3I‐PTMH ) crystals which is characterized by a high photoluminescence quantum yield (PLQY 91 %) and color purity (CIE coordinates 0.66, 0.34). The emission originates from the doublet excited state of the neutral radical 3I‐PTMR , which is spontaneously formed and becomes embedded in the 3I‐PTMH matrix. The radical defect can also be deliberately introduced into 3I‐PTMH crystals which maintain a high PLQY with up to 4 % radical concentration. The immobilized iodinated radical demonstrates excellent photostability (estimated half‐life >1 year under continuous irradiation) and intriguing luminescent lifetime (69 ns). TD‐DFT calculations demonstrate that electron‐donating iodine atoms accelerate the radiative transition while the rigid halogen‐bonded matrix suppresses the nonradiative decay.

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Journal of the American Chemical SocietyDOI: 10.1021/jacs.0c07166

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Azobenzene under lockdown : Photoisomerizable molecules such as azobenzene convert light directly into chemical energy, however, with a low energy efficiency. By systematically reducing the conformational flexibility of azobenzene and thus preventing unproductive photochemical pathways, the energy conversion efficiency was increased from 1.4 % to 18.1 %, which is the largest of any known photochromic compound.

Abstract

Photochromic systems have been used to achieve a number of engineering functions such as light energy conversion, molecular motors, pumps, actuators, and sensors. Key to practical applications is a high efficiency in the conversion of light to chemical energy, a rigid structure for the transmission of force to the environment, and directed motion during isomerization. We present a novel type of photochromic system (diindane diazocines) that converts visible light with an efficiency of 18 % to chemical energy. Quantum yields are exceptionally high with >70 % for the cis–trans isomerization and 90 % for the back‐reaction and thus higher than the biochemical system rhodopsin (64 %). Two diastereomers (meso and racemate) were obtained in only two steps in high yields. Both isomers are directional switches with high conversion rates (76–99 %). No fatigue was observed after several thousands of switching cycles in both systems.

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Journal of the American Chemical SocietyDOI: 10.1021/jacs.0c00871

https://ift.tt/2WEEfL3

Just installed new 65 watt quantum board to replace 150 watt hps and am wondering if anyone has experience flowering under just one 65 watt quantum board. What sort of yield can i expect? I'm growing 4 northern light cross clones in 6 inch pots using sog method and if all goes well i will purchase a second 65 watt quantum board and have 8 clones total. Until then i would like to see what just one will pull.

Temps hover around 82F when lights are on, 75F when off. Humidity is 45% when lights are on, 65% when off.

What are you able to harvest dry in a 3x3 with HLG 300 V2 - 275W from wall. For personal use looking for around 1lb dry. How realistic is that for a new grower?

I've tried researching this to no avail. Obviously, what I'm asking here is just a version the quantum measurement problem.

But, is there some phenomenon that causes a state to collapse into an eigenstate of whatever operator is observed? Why do interactions with classical systems behave in this way?

Perhaps someone who has studied decoherence knows the answer to this.

Edit: Thanks for all the responses! Let me clarify my question. I think I've muddled up this post by accidentally asking two different questions.

1. Why are measured values real, when QM works using complex numbers?

2. (The more important question to me) Why do quantum systems, after interacting with some classical system, collapse to eigenstates of a particular operator? In addition, how do they "know" which operator's eigenstate to collapse to?

They are both amines. One is a tertiary amine containing two ethanesulfonate groups on the nitrogen. The other is a tertiary amine as well but contains one ethane sulfonate group on the nitrogen and one methyl group. They are all in solution.

for those with the same question I found two resources:
http://www.spectra.arizona.edu/
http://www.fluorophores.tugraz.at/substance/706
But finding QYs listed by manufacturers or investigated in literature is proving difficult even for common dyes. I have access to Caltech's library so it's not like I am missing articles.

I need to compare the dyes before procuring them so actual methods will not help without published results.

Thanks all!

We report red luminescence in off‐white tris(iodoperchlorophenyl)methane (3I‐PTMH) crystals which is characterized by high photoluminescence quantum yield (PLQY 91%) and color purity (CIE coordinates 0.66, 0.34). The emission originates from the doublet excited state of the neutral radical 3I‐PTMR that is spontaneously formed and becomes embedded in 3I‐PTMH matrix. The radical defect can also be deliberately introduced in 3I‐PTMH crystals which maintain high PLQY up to 4% radical concentration. The immobilized iodinated radical demonstrates excellent photostability (estimated half‐life >1 year under continuous irradiation) and intriguing luminescent lifetime (69 ns). TD‐DFT calculations demonstrate that electron‐donating iodine atoms accelerate the radiative transition while the rigid halogen‐bonded matrix suppresses the non‐radiative decay.

https://ift.tt/3j9vKzT

Journal of the American Chemical SocietyDOI: 10.1021/jacs.0c06039

https://ift.tt/39m7gPS

Photochromic systems have been used to achieve a number of engineering functions such as light energy conversion, molecular motors, pumps, actuators, and sensors. Key to p rac tical applications is a high efficiency in conversion of light to chemical energy, a rigid structure for the trans mission of force to the environment and directed motion during isomerization. We present a novel type of photochromic system (diindane diazocines), that converts visible light with an efficiency of 18% to chemical energy. Quantum yields are exceptionally high with >70% for the cis‐trans isomerization and 90% for the back‐reaction and thus higher than the biochemical system rhodopsin (64%). Two diastereomers ( meso and rac emate) were obtained in only two steps in high yields. Both isomers are directional switches with high conversion rates (76‐99%). No fatigue was observed after several thousands of switching cycles in both systems.

https://ift.tt/2SmqDRH