Article
Energy & Fuels
Kazuki Kohzuki, Rei Shirouchi, Shin-ichiro Natsuda, Toshiharu Saito, Yuji Sakamoto, Yasunari Tamai
Summary: Suppressing charge recombination is crucial for enhancing the power conversion efficiency of organic solar cells (OSCs). The formation of both singlet and triplet charge transfer (CT) states in OSCs indicates that charge recombination via the triplet excited state is the main pathway for deactivation. However, it has been shown that charge separation from triplet excitons can occur in nonfullerene acceptor (NFA)-based OSCs, emphasizing the significance of minimizing the energy difference between singlet and triplet excited states of NFAs to suppress charge recombination.
Article
Chemistry, Multidisciplinary
Christopher C. S. Chan, Chao Ma, Xinhui Zou, Zengshan Xing, Guichuan Zhang, Hin-Lap Yip, Robert A. Taylor, Yan He, Kam Sing Wong, Philip C. Y. Chow
Summary: Transient optical spectroscopy is used to quantify the temperature-dependent charge separation and recombination dynamics in two non-fullerene organic photovoltaic systems. The results show different charge generation rates and stored energy between charge pairs at different temperatures. The thermally activated charge separation in PM6:Y6 is observed, leading to a faster charge separation rate at room temperature.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Ziyu Yang, Zhiyong Liu, Lan Chen
Summary: In order to achieve efficient organic photovoltaics, a ternary strategy was adopted by adding efficient long-wavelength light-absorption donor material PSBTBT as the third component, and using D18-Cl:BTP-eC9 binary film as the host photoactive layer. This improved the absorption spectrum and energy transfer within both donor materials. The addition of a small amount of PSBTBT slightly changed the morphology of the photoactive layer, but resulted in a higher power conversion efficiency of 17.35%.
ACS APPLIED POLYMER MATERIALS
(2023)
Review
Biochemistry & Molecular Biology
Andrea M. Schmidt, Mario J. F. Calvete
Summary: Phthalocyanines, as exquisite compounds with favorable properties, have seen steady growth in applications, particularly in cutting-edge technologies relying on their great photophysical properties. The spotlight remains on phthalocyanines, with many researchers providing vivid reports on their innovative use in photo-applications.
Article
Chemistry, Physical
Neha Luhakhra, Sanjiv Kumar Tiwari
Summary: Organic-inorganic hetero-junction based catalysts with efficient charge separation ability for superior photocatalytic activity have been developed by chemical methods. The TiO2/PPy hetero-junction composite exhibits enhanced efficiency for the degradation of the toxic organic dye methylene blue (MB) through charge transfer route. Polaron and bipolaron in PPy and TiO2/PPy composite give rise to broad curves in UV-Vis spectra. The de-localized polaron was further detected by electron spin resonance (ESR), and the effect of polaron-bipolaron on the structure of PPy and TiO2/PPy composite was explored by Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) investigated the oxidation state of different species and electronic structures below the Fermi level, providing molecular orbitals insight and charge transfer state across the heterojunction TiO2/PPy composite. The energy positions for TiO2 and PPy confirm the hetero-junction in the composite.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2023)
Article
Chemistry, Multidisciplinary
Shu-Wen Zheng, Hai Wang, Lei Wang, Hai-Yu Wang
Summary: This study investigates the ultrafast exciton dynamics in vdW heterostructures built on 2D materials using pump-probe spectroscopy. The results reveal a two-step exciton transfer process in trilayer structures and the observation of interlayer exciton transfer in bilayer structures. The findings provide a deeper understanding of charge transfer in 2D vdW heterostructures.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Computer Science, Interdisciplinary Applications
Leandro Benatto, Omar Mesquita, Lucimara S. Roman, Rodrigo B. Capaz, Graziani Candiotto, Marlus Koehler
Summary: Photoluminescence Quenching Simulator (PLQ-Sim) is a user-friendly software for studying the dynamics of photoexcited states at the interface between organic semiconductors. It provides important information on organic photovoltaic and photothermal devices and calculates transfer rates and quenching efficiency.
COMPUTER PHYSICS COMMUNICATIONS
(2024)
Article
Energy & Fuels
Ting Wang, Xunchang Wang, Renqiang Yang, Chaoxu Li
Summary: This review discusses the successful application of Forster resonance energy transfer (FRET) in promoting the efficiencies of ternary blend organic solar cells (TOSCs), highlighting the diverse framework structures of FRET pairs and the role of FRET theory in the photoconversion process, including exciton harvesting, exciton diffusion, and charge generation. Existing challenges and future research directions of FRET applications in TOSCs are also proposed.
Article
Chemistry, Physical
Seihou Jinnai, Kasumi Murayama, Keisuke Nagai, Megumi Mineshita, Kosaku Kato, Azusa Muraoka, Akira Yamakata, Akinori Saeki, Yasuhiro Kobori, Yutaka Ie
Summary: This study introduces a non-fused nonfullerene acceptor (NFA) by utilizing a spiro-substituted 2,7-bis(2-ethylhexyl)fluorene (FT) as a rigid and bulky linker unit. The results show that the introduction of the FT unit leads to the formation of a rigid molecular structure, resulting in improved power conversion efficiency of organic solar cells.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Review
Chemistry, Multidisciplinary
Yasunari Tamai
Summary: The power conversion efficiencies of organic solar cells (OSCs) have rapidly improved, exceeding 19%. This review focuses on fundamental and cutting-edge research that explains the efficient generation of photocurrent in OSCs and discusses future research directions for further improvements in performance.
Article
Chemistry, Multidisciplinary
Tao Li, Bin Li, Haoxiang Zhou, Jun Wang, Gang Ni, Wanli Ma, Chuanxiang Sheng, Jianyu Yuan, Haibin Zhao
Summary: This study reports on the ultrafast dynamics of charge transfer and exciton dissociation in single-material organic solar cells for the first time. It is found that the intramolecular interface in the block copolymer has a higher transfer rate, and the dilute PBDB-T-b-PTY6 film has faster exciton dissociation. By optimizing ordering, the power conversion efficiency of organic solar cells can be improved.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Multidisciplinary Sciences
Pavel Maly, Julian Luettig, Peter A. Rose, Arthur Turkin, Christoph Lambert, Jacob J. Krich, Tobias Brixner
Summary: Quantum states depend on the coordinates of all their constituent particles, with essential multi-particle correlations. Time-resolved laser spectroscopy is widely used to probe the energies and dynamics of excited particles and quasiparticles. However, nonlinear signals from single- and multiple-particle excitations are all present simultaneously and cannot be disentangled without a priori knowledge of the system.
Article
Chemistry, Physical
Dongdong Xia, Zhou Zhang, Chaowei Zhao, Jing Wang, Jun Xia, Guihua Chen, Shuai Li, Zheng Tang, Shengyong You, Weiwei Li
Summary: By introducing a fullerene acceptor into the binary photo-active layer, the ternary organic solar cells achieved a higher power conversion efficiency compared to binary solar cells, mainly due to optimized morphology and balanced hole and electron mobilities that help suppress charge recombination and increase photocurrent.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Physical
Kang-Ning Zhang, Zhi-Nan Jiang, Tong Wang, Jia-Wei Qiao, Lin Feng, Chao-Chao Qin, Hang Yin, Shu-Kong So, Xiao-Tao Hao
Summary: In this study, the enhancement of exciton migration behaviors in PM6:IT4F:PC71BM and PM6:BTP-4Cl:PC71BM ternary devices was achieved by simultaneously improving efficiency and thermal stability. The coexistence of dual Forster-type energy transfer and the addition of PC71BM contributed to the directed exciton diffusion and stabilized the energy donors, leading to more favorable multi-length scale morphologies.
Article
Nanoscience & Nanotechnology
Lijian Zuo, Sae Byeok Jo, Yaokai Li, Yuhuan Meng, Ryan J. Stoddard, Yun Liu, Francis Lin, Xueliang Shi, Feng Liu, Hugh W. Hillhouse, David S. Ginger, Hongzheng Chen, Alex K-Y Jen
Summary: Research shows that the "dilution effect" mechanism in multi-component organic solar cells can enhance luminescence quantum efficiency and open-circuit voltage, achieving high energy conversion efficiency.
NATURE NANOTECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Yang Lu, Zi-Di Yu, Hio-Ieng Un, Ze-Fan Yao, Hao-Yang You, Wenlong Jin, Liang Li, Zi-Yuan Wang, Bo-Wei Dong, Stephen Barlow, Elena Longhi, Chong-an Di, Daoben Zhu, Jie-Yu Wang, Carlos Silva, Seth R. Marder, Jian Pei
Summary: A simple solution-based co-deposition method has been reported to achieve high conductivity n-doped polymers. These polymers exhibit surprising structural tolerance and excellent miscibility with commonly used n-dopants, allowing high concentrations and high mobility of charge carriers simultaneously, resulting in excellent electrical conductivity and thermoelectric performance.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Ilaria Bargigia, Lisa R. Savagian, Anna M. Osterholm, John R. Reynolds, Carlos Silva
Summary: The study investigates the electrochemically induced charged states in conjugated polymers, particularly in an oligoether-functionalized 3,4-propylenediorythiophene (ProDOT) copolymer. The research reveals a precursor electronic state with charge-transfer character that precedes polaron formation and bulk electronic conductivity. Further analysis shows the coupling of this state with primary excitons and electrochemically induced charge-separated states, providing insights into the energetic landscape of a heterogeneous polymer-electrolyte system.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Deepak Thrithamarassery Gangadharan, David Valverde-Chavez, Andres-Felipe Castro-Mendez, Vivek Prakash, Ricardo Izquierdo, Carlos Silva, Dongling Ma, Juan-Pablo Correa-Baena
Summary: The addition of bulky phenylethyl ammonium (PEA) cation in the precursor solution improved the performance of perovskite solar cells and induced a redshift in sample absorption as confirmed by transient absorption spectroscopy. The improved band alignment of perovskite with other materials due to PEA addition aids in electron injection and enhances photocurrents. Furthermore, PEA addition suppresses halide segregation, improving material stability in lead-free perovskite solar cells.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Applied
Rodrigo M. Barba-Barba, Marwa Chammam, Gabriel Ramos-Ortiz, Dymytrii Listunov, Jayaramakrishnan Velusamy, Mario Rodriguez, Ramon Carriles, Carlos Silva, Carine Duhayon, Brice Kauffmann, Valerie Maraval, Remi Chauvin
Summary: The study compares the optical properties of different structures of carbo-benzenes, finding that the carbomerization leads to lower energy electronic excitations and higher molar extinction coefficients compared to the parent molecules. Additionally, the carbomers exhibit a broad photoluminescence band with transitions from multiple excited states contrary to Kasha's rule.
Article
Chemistry, Multidisciplinary
Liyang Yu, Egon Pavlica, Ruipeng Li, Yufei Zhong, Carlos Silva, Gvido Bratina, Christian Muller, Aram Amassian, Natalie Stingelin
Summary: Semiconducting mesocrystalline bulk polymer specimens with near-intrinsic properties were successfully demonstrated using channel-die pressing method. The persistent mesocrystalline arrangement at macroscopic scales allowed reliable evaluation of electronic charge-transport anisotropy along all three crystallographic axes, with high mobilities found along the pi-stacking. The versatile approach showed promise as a straightforward, readily scalable method to fabricate bulk semiconducting polymer structures with properties typically only accessible by the tedious growth of single crystals.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Esteban Rojas-Gatjens, Carlos Silva-Acuna, Ajay Ram Srimath Kandada
Summary: The study focuses on the phonon-phonon scattering probabilities and their relationship with electronic transitions in the Ruddlesden Popper metal-halide lattice, identifying the main anharmonic phonon governing the photophysics. By analyzing the temperature-dependent coherent phonon lifetimes, the dominant anharmonic phonon is isolated and its interaction strength quantified. Some phonons exhibit temperature-independent coherence lifetimes, suggesting predominantly harmonic nature, while exciton dynamics are mainly influenced by anharmonic phonons.
MATERIALS HORIZONS
(2022)
Article
Energy & Fuels
Jonatan Rodriguez-Rea, Marisol Guizado-Rodriguez, Jose-Luis Maldonado, Gabriel Ramos-Ortiz, Jose Ulises Reveles, Carlos Silva, Victor Barba, Esmeralda Monserrat Saucedo-Salazar, Maria Teresa Rodriguez Hernandez
Summary: A series of PFDPP copolymers based on fluorene and diketopyrrolopyrrole monomers were successfully synthesized via direct arylation polycondensation, with the optimal catalyst amount being 12% resulting in a high yield of 81.5% and high molecular weight. These copolymers exhibit distinctive donor-acceptor structure, good fluorescence performance, and relatively high two-photon absorption cross-section.
Article
Chemistry, Physical
Ajay Ram Srimath Kandada, Hao Li, Eric R. Bittner, Carlos Silva-Acuna
Summary: The homogeneous photoluminescence spectral linewidth in semiconductors can provide valuable information about the coupling of primary photo excitations with their dynamic environment and between multiparticles. Temperature-dependent steady-state photoluminescence spectroscopy can be used to separate homogeneous and inhomogeneous contributions to the total line width. However, in cases where the homogeneous and inhomogeneous line widths are comparable, nonlinear coherent optical spectroscopies offer a better way to separate these contributions. These techniques have been applied to study Ruddlesden-Popper metal halides and have provided insights into exciton-phonon and exciton-exciton scattering mechanisms.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Hao Li, S. A. Shah, Eric R. Bittner, Andrei Piryatinski, Carlos Silva-Acuna
Summary: In this paper, a stochastic model is developed to explain non-stationary background processes produced by broad-band pulsed laser stimulation. The contribution of pair-fluctuations is considered, and the connection between observed spectral fluctuations and spectral density of the environment is established using the Ito transformation. Two limiting cases are explored, and their implications on spectral dynamics are discussed.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Carlo Andrea Riccardo Perini, Esteban Rojas-Gatjens, Magdalena Ravello, Andres-Felipe Castro-Mendez, Juanita Hidalgo, Yu An, Sanggyun Kim, Barry Lai, Ruipeng Li, Carlos Silva-Acuna, Juan-Pablo Correa-Baena
Summary: This study explores the impact of bulky-cation-modified interfaces on the stability of halide perovskite solar cells. The results demonstrate the thermal instability of the bulky-cation interface layers used in state-of-the-art solar cells, which significantly affects the performance and operation of the devices. The type of cation used for surface treatment also influences the extent of these changes, with long carbon chains providing more stable interfaces.
ADVANCED MATERIALS
(2022)
Correction
Chemistry, Physical
Hao Li, S. A. Shah, Eric R. Bittner, Andrei Piryatinski, Carlos Silva-Acuna
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Ilaria Bargigia, Elizabeth Gutierrez-Meza, David A. Valverde-Chavez, Sarah R. Marques, Ajay Ram Srimath Kandada, Carlos Silva
Summary: It has been found that there is an incoherent nonlinear response as an unexpected background in two-dimensional coherent electronic spectroscopy. By simulating the effect of incoherent mixing on the photocurrent signal and applying external action on the circuit used for phase-sensitive detection, an effective strategy to recognize the presence of incoherent mixing in 2D data has been identified.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Jonatan Rodriguez-Rea, Marisol Guizado-Rodriguez, Jose-Luis Maldonado, Gabriel Ramos-Ortiz, J. Ulises Reveles, Carlos Silva, Victor Barba, Esmeralda M. Saucedo-Salazar, Maria Teresa Rodriguez Hernandez
Summary: A range of D-A oligomers based on TT, BTT, and DPP were synthesized using eco-friendly direct arylation polymerization. These oligomers exhibited notable properties in terms of infrared photoluminescence and optical nonlinear absorption. The dynamics of excited states in these oligomers were studied in solution, nanoparticles, and solid films. Additionally, the application of a BTT derivative in ternary organic solar cells resulted in an improvement in conversion efficiency.
Article
Chemistry, Physical
Jameel Ahmed Bhutto, Zhonglin He, Jawayria Najeeb, Sumaira Naeem, Eman A. Mahmoud, Hosam O. Elansary
Summary: Designing novel drugs using data-driven and virtual screening approaches, such as machine learning and data mining, is a popular research topic in the pharmaceutical industry. In this study, ML models were trained using data collected from academic research articles, and molecular descriptors were utilized. The best ML models were selected and optimized to identify potential compounds for aromatase inhibitors. These models accurately predicted the inhibition values of compounds in a database, and new compounds were designed based on the predictions. Overall, this study demonstrates the potential significance of data-driven and virtual screening approaches in pharmaceutical research.
Article
Chemistry, Physical
Raphael M. Tromer, Isaac M. Felix, Levi C. Felix, Leonardo D. Machado, Cristiano F. Woellner, Douglas S. Galvao
Summary: This study investigates the adsorption mechanisms of hydrogen atoms and molecules on 2D metallic porphyrins using DFT simulations. The results show that hydrogen atoms are chemisorbed while hydrogen molecules are physisorbed. Vanadium and chromium embedded porphyrins exhibit the highest maximum adsorption energies for hydrogen atoms, while scandium embedded porphyrins exhibit the highest maximum adsorption energy for hydrogen molecules. Furthermore, charge transfer is minimal for physisorption and significant for chemisorption. Uniaxial strain has minimal effects on the adsorption properties of 2D metallic porphyrins.
Article
Chemistry, Physical
Ankur Kanti Guha
Summary: This study examines the genuineness of a proposed quadruple bond in AeF(-) (Ae = Be-Ba) using electron localization function (ELF). The ELF analysis reveals the presence of a disynaptic Ae-F basin with electron integration much lower than expected for a quadruple bond. These bonds are classified as Charge-Shift bonds due to the excess kinetic energy in the bonding basins.
Article
Chemistry, Physical
X. F. Yang, Y. J. Dong, H. L. Yu, X. X. Tao, Y. S. Liu
Summary: This study investigates the spin-polarized transport properties of an iron-complex molecule sandwiched between two ferromagnetic zigzag-edged graphene nanoribbon electrodes. The results show the presence of single-spin switching effect, perfect spin filtering effect, and negative differential electrical and thermoelectric resistance in the molecular device. These findings suggest the potential applications of iron-complex molecular devices in the next-generation spin electric and thermoelectric devices.
Article
Chemistry, Physical
Zhengwei Yan, Tianchu Zhao, Qinghua Ren
Summary: In this study, the chemically accurate hybrid MP2:(PBE + D2) + Delta CCSD(T) method was used to investigate the transition states of alkenes reacting with the Al(2)O(7) Bronsted acid site in H-ferrierite (H-FER). The results showed that the MP2 + Delta CC intrinsic energy barriers were higher than the corresponding PBE + D2 intrinsic energy barriers, and the relative energies of the transition states decreased with the increase of the carbon number. For the reactant of propene, the conversion into 2-propoxide had a lower energy barrier compared to the conversion into 1-propoxide.
Article
Chemistry, Physical
Yutong Yao, Qihang Liang, Fawei Zheng, Menglei Li
Summary: In this study, first-principle calculations were used to investigate the structural, electronic, and superconducting properties of hydrogen-rich plutonium polyhydrides under high pressures. The results showed that these systems exhibited metallic behavior, with a low superconducting transition temperature. Additionally, it was found that the f electrons in plutonium had a detrimental effect on the superconductivity in these polyhydrides.
Article
Chemistry, Physical
Ryan Lambert, Arthur C. Reber, Turbasu Sengupta, Shiv N. Khanna
Summary: This study demonstrates how the placement of terminal ligands and the deposition of alkali atoms control the band gap energy and placement of band edges in phosphorene nanoribbons. The work function is significantly affected by the induced dipole of the terminal groups, and the band gap can be manipulated by adding alkali atoms on the surface.
Article
Chemistry, Physical
Daiya Nagai, Akimasa Fujihara
Summary: The effects of intermolecular interactions on the reactivity of hydrogen-bonded clusters of adenosine and tryptophan in the gas phase were investigated using water adsorption and ultraviolet photoexcitation. The results showed that water adsorption weakened the intermolecular interactions between adenosine and tryptophan in the clusters and inhibited the photoinduced glycosidic bond cleavage of adenosine.
Article
Chemistry, Physical
Xiaoping Han, Maamar Benkraouda, Zhiyuan Wang, Zongsheng Zhang, Noureddine Amrane
Summary: This study investigates the effects of Fe substitution and its complex with Sb vacancy on the magnetic properties and optoelectronic functionalities of antimonene. It is found that Fe substitution induces magnetism and promotes optical absorption, while further incorporation of VSb stabilizes Fe dopant and enhances both magnetism and photoabsorption. This work has implications in developing spintronic and optoelectronic applications.
Article
Chemistry, Physical
Yifei Zhang, Xi Wang, Na Liu, Faming Lu
Summary: Understanding the ultrafast electron transfer (ET) processes involving various vibronic excitation in biological systems is challenging. This study investigated the excitation dependence of the photo-induced ET dynamics by selecting mutants in flavodoxin with different ET lifetimes. The results showed that increasing excitation energies resulted in higher vibrational excitation in products for the ultrafast ET processes, but no dependence was found for slower ET due to complete vibrational relaxation.
Article
Chemistry, Physical
Xiang Ge, Jigang Zhao, Xiangqian Yuan, Haitao Shen, Shiyong Wu
Summary: This study investigated the catalytic splitting of 1,1,2-TCE and found that CsCl showed the best catalytic effect. Characterization results of CO2-TPD and NH3-TPD suggested that alkaline sites were beneficial for the selective generation of VDC.
Article
Chemistry, Physical
Theerapol Thurakitseree, Arunothai Rattanachata, Hideki Nakajima, Somruthai Phothiphiphit, Surasak Kuimalee, Pimpun Suknet
Summary: Thin film nitrogen-doped SWCNTs were synthesized using floating-catalyst chemical vapor deposition. The incorporation of low levels of nitrogen into the carbon network resulted in predominance of substitutional and pyridinic nitrogens, changing the electronic structure of the SWCNT film to n-type doping. X-ray absorption spectroscopy revealed the localized structures of carbon and nitrogen bonding environments. The formation of a p-n junction was observed from the I-V characteristic of the N-doped SWCNT heterojunction diode, indicating n-type behavior.
Article
Chemistry, Physical
Chaithanya Kondur, Kelly A. Stephani
Summary: This study investigates the complex dynamics involved in the recombination of atomic nitrogen to form molecular nitrogen and explores the impact of a third body on the recombination dynamics. The results show that the recombination probability is highest for collisions with low translational energies and low time lags. Additionally, a novel rate coefficient expression is developed to evaluate low temperature recombination rate coefficients at a lower computational cost.
Article
Chemistry, Physical
Bingyao Wang, Zhongneng Zhou, Qin Zhang, Bo Dong, Xiu-Wen Kang, Bei Ding
Summary: In this study, two well-separated excited-state vibrational bands were observed in ethanol for indole derivatives with CN substituted on the six-membered rings (4-7CNIs) using UV/Vis pumped IR detection. A population redistribution process between the L-1(a) and L-1(b) states was observed in 4-7CNIs with a time constant of about 20 ps, driven by excitation-induced solvation relaxation. Only a single peak corresponding to the L-1(b) state was detected in 3CNI where the CN is attached on the five-membered ring.
Article
Chemistry, Physical
Ruoqi Zhang, Delu Gao, Yixuan Li, Dunyou Wang
Summary: The adsorption of CO on transition metal clusters supported by divacancy graphene has been studied, revealing that the supported clusters exhibit stronger adsorption capacity for CO due to the orbital coupling and induced electrostatic interaction.
