Pub Date : 2025-07-21DOI: 10.1016/j.susc.2025.122813
Weiduo Wang
An in-depth understanding of the relationship between the structure and properties of physical vapor deposited (PVD) glass films is crucial for their applications at the nanoscale within industrial contexts. This study employs a coarse-grained simulation methodology to model PVD films composed of N,N-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD) molecules with varying thicknesses. The findings indicate that, in contrast to liquid-quenched glasses (LQG), PVD glasses exhibit a higher elastic modulus and a lower loss modulus in the bulk, corroborating previous research that highlights enhanced mechanical stability. This work also shows that a region adjacent to the substrate of the PVD films has an exceptionally elevated elastic modulus that is correlated with changes in loss modulus, molecular orientation, and out-of-plane mobility. This phenomenon may be attributed to the surface-substrate effect resulting from the PVD process, and this effect may facilitate incoming molecule to a deeper energy state, resulting in a remarkable thermal and mechanical stability of ultrathin films.
{"title":"Interfacial effect on the formation and properties of stable glasses","authors":"Weiduo Wang","doi":"10.1016/j.susc.2025.122813","DOIUrl":"10.1016/j.susc.2025.122813","url":null,"abstract":"<div><div>An in-depth understanding of the relationship between the structure and properties of physical vapor deposited (PVD) glass films is crucial for their applications at the nanoscale within industrial contexts. This study employs a coarse-grained simulation methodology to model PVD films composed of N,N-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD) molecules with varying thicknesses. The findings indicate that, in contrast to liquid-quenched glasses (LQG), PVD glasses exhibit a higher elastic modulus and a lower loss modulus in the bulk, corroborating previous research that highlights enhanced mechanical stability. This work also shows that a region adjacent to the substrate of the PVD films has an exceptionally elevated elastic modulus that is correlated with changes in loss modulus, molecular orientation, and out-of-plane mobility. This phenomenon may be attributed to the surface-substrate effect resulting from the PVD process, and this effect may facilitate incoming molecule to a deeper energy state, resulting in a remarkable thermal and mechanical stability of ultrathin films.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"761 ","pages":"Article 122813"},"PeriodicalIF":2.1,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144714192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-16DOI: 10.1016/j.susc.2025.122812
Ali Raza Chachar , Basheer Ahmed Kalwar , Muhammad Rafique , Amir Mahmood Soomro , Zaheer Ahmed , Ahsanullah Memon
Partial discharges in SF6 circuit breakers decompose SF6 into low-fluorine gases, which react with trace moisture to form corrosive acids, degrading contacts and impairing arc quenching capacity, necessitating a 24/7 monitoring system for early detection and prevention. In this work, carbon boronitride (BC6N) monolayer is investigated for potential application of SF6 decomposed gases SO2, SO2F2, SOF2, H2S, and HF through DFT calculations. Adsorption performance through adsorption energy, charge density difference, density of states, while sensitivity through band structures, work function and transport transmission and recovery through recovery time calculations are evaluated. Results show that pristine BC6N is weakly absorbing the gas molecules, however, BC6N decorated with Fe and Co atoms chemisorbs the gas molecules with enhanced adsorption energy -1.01 to -1.61 eV and -0.95 to -1.58 eV respectively. Diffusion energy barrier calculation confirms that Fe and Co atoms don’t make clusters. Sensitivity of Fe/BC6N and Co/BC6N to gas molecules respectively follows: (67.5 % and 72.9 %) for SO2F2> (70.8 % and 65 %) for SOF2> (68.7 % and 62.5 %) for SO2> (64.5 % and 57.5 %) for H2S> (58.3 % and 50 %) for HF. Recovery time calculations results show that strongest adsorbed SO2F2 molecule takes 117.5 h to be desorbed at 498 K temperature, which is considerably shortened to 1.69 nanoseconds upon UV exposure. Our proposed substrates can actively adsorb, sense and instantaneously desorb the target gas molecules, proving that Fe/BC6N and Co/BC6N can potentially be highly sensitive and reusable gas sensors.
{"title":"Adsorption and sensing SF6 decomposed gases; SO2, SO2F2, SOF2, H2S, and HF on Fe and Co decorated monolayer BC6N. First-principles study","authors":"Ali Raza Chachar , Basheer Ahmed Kalwar , Muhammad Rafique , Amir Mahmood Soomro , Zaheer Ahmed , Ahsanullah Memon","doi":"10.1016/j.susc.2025.122812","DOIUrl":"10.1016/j.susc.2025.122812","url":null,"abstract":"<div><div>Partial discharges in SF<sub>6</sub> circuit breakers decompose SF<sub>6</sub> into low-fluorine gases, which react with trace moisture to form corrosive acids, degrading contacts and impairing arc quenching capacity, necessitating a 24/7 monitoring system for early detection and prevention. In this work, carbon boronitride (BC<sub>6</sub>N) monolayer is investigated for potential application of SF<sub>6</sub> decomposed gases SO<sub>2</sub>, SO<sub>2</sub>F<sub>2</sub>, SOF<sub>2</sub>, H<sub>2</sub>S, and HF through DFT calculations. Adsorption performance through adsorption energy, charge density difference, density of states, while sensitivity through band structures, work function and transport transmission and recovery through recovery time calculations are evaluated. Results show that pristine BC<sub>6</sub>N is weakly absorbing the gas molecules, however, BC<sub>6</sub>N decorated with Fe and Co atoms chemisorbs the gas molecules with enhanced adsorption energy -1.01 to -1.61 eV and -0.95 to -1.58 eV respectively. Diffusion energy barrier calculation confirms that Fe and Co atoms don’t make clusters. Sensitivity of Fe/BC<sub>6</sub>N and Co/BC<sub>6</sub>N to gas molecules respectively follows: (67.5 % and 72.9 %) for SO<sub>2</sub>F<sub>2</sub>> (70.8 % and 65 %) for SOF<sub>2</sub>> (68.7 % and 62.5 %) for SO<sub>2</sub>> (64.5 % and 57.5 %) for H<sub>2</sub>S> (58.3 % and 50 %) for HF. Recovery time calculations results show that strongest adsorbed SO<sub>2</sub>F<sub>2</sub> molecule takes 117.5 h to be desorbed at 498 K temperature, which is considerably shortened to 1.69 nanoseconds upon UV exposure. Our proposed substrates can actively adsorb, sense and instantaneously desorb the target gas molecules, proving that Fe/BC<sub>6</sub>N and Co/BC<sub>6</sub>N can potentially be highly sensitive and reusable gas sensors.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"761 ","pages":"Article 122812"},"PeriodicalIF":1.8,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-10DOI: 10.1016/j.susc.2025.122807
A. Mizuhara , T. Fukuda , K. Umezawa
Silver-induced surface atomic structures on a Ni(110) surface up to 1 ML between room temperature and 673 K were studied using ultrahigh vacuum scanning tunneling microscopy and low-energy electron diffraction. A 0.72 ML-Ag-deposited surface at room temperature showed monolayer-high aggregated Ag stripes separated by periodic trenches and shallow troughs. Ag stripes consisted of six aggregated Ag atoms in the direction to form a one-dimensional (1-D) cluster and it extended in the direction with 3 × 9 and surface superstructures. Some Ag stripes were bridged by fuzzy regions where 1-D fluctuating Ag atoms were adsorbed on the substrate Ni(110) row. Above 473 K, the 1-D Ag cluster consisting of seven atoms formed Ag stripes with periodicity of the surface unit cell in the direction, and the Ni(110) substrate surface was exposed between the Ag stripes. The stability of the Ag stripes was confirmed by conducting first principles calculations and through simulated STM images.
{"title":"Initial stage of silver overlayer formation on the Ni(110) surface","authors":"A. Mizuhara , T. Fukuda , K. Umezawa","doi":"10.1016/j.susc.2025.122807","DOIUrl":"10.1016/j.susc.2025.122807","url":null,"abstract":"<div><div>Silver-induced surface atomic structures on a Ni(110) surface up to 1 ML between room temperature and 673 K were studied using ultrahigh vacuum scanning tunneling microscopy and low-energy electron diffraction. A 0.72 ML-Ag-deposited surface at room temperature showed monolayer-high aggregated Ag stripes separated by periodic trenches and shallow troughs. Ag stripes consisted of six aggregated Ag atoms in the <span><math><mrow><mo>[</mo><mn>1</mn><mover><mrow><mn>1</mn></mrow><mrow><mo>̄</mo></mrow></mover><mn>0</mn><mo>]</mo></mrow></math></span> direction to form a one-dimensional (1-D) cluster and it extended in the <span><math><mrow><mo>[</mo><mn>001</mn><mo>]</mo></mrow></math></span> direction with 3 × 9 and <span><math><mfenced><mrow><mtable><mtr><mtd><mn>3</mn></mtd><mtd><mn>0</mn></mtd></mtr><mtr><mtd><mo>±</mo><mn>1</mn></mtd><mtd><mn>9</mn></mtd></mtr></mtable></mrow></mfenced></math></span> surface superstructures. Some Ag stripes were bridged by fuzzy regions where 1-D fluctuating Ag atoms were adsorbed on the substrate Ni(110) row. Above 473 K, the 1-D Ag cluster consisting of seven atoms formed Ag stripes with <span><math><mrow><mn>12</mn><mo>×</mo></mrow></math></span> periodicity of the surface unit cell in the <span><math><mrow><mo>[</mo><mn>1</mn><mover><mrow><mn>1</mn></mrow><mrow><mo>̄</mo></mrow></mover><mn>0</mn><mo>]</mo></mrow></math></span> direction, and the Ni(110) substrate surface was exposed between the Ag stripes. The stability of the Ag stripes was confirmed by conducting first principles calculations and through simulated STM images.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"761 ","pages":"Article 122807"},"PeriodicalIF":2.1,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144653597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-09DOI: 10.1016/j.susc.2025.122811
Matteo Cargnello , Sen Zhang
{"title":"Well-defined nanoparticles: synthesis, characterization, applications in the XXI century (Surface Science special issue)","authors":"Matteo Cargnello , Sen Zhang","doi":"10.1016/j.susc.2025.122811","DOIUrl":"10.1016/j.susc.2025.122811","url":null,"abstract":"","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"761 ","pages":"Article 122811"},"PeriodicalIF":1.8,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144841961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-04DOI: 10.1016/j.susc.2025.122810
Om Shree Rijal, Hari Krishna Neupane, Pitamber Shrestha, Shriram Sharma, Leela Pradhan Joshi, Rajendra Parajuli
The present work investigates the structural, electronic, and magnetic properties of a (3 × 3 × 1) supercell monolayer of Mn doped ZnO (Mn-ZnO), CO adsorbed on ZnO (CO-ZnO), NH3 adsorbed on ZnO (NH3-ZnO), and CO & NH3 adsorbed on Mn-ZnO (CO-Mn-ZnO, & NH3−Mn-ZnO) structures. Density functional theory (DFT) method with a projected augmented basis set has been used for this study, by employing two different exchange-correlation functionals: GGA-PBE and GGA-PBE+U through the Vienna-Ab-intio Simulation Package (VASP) software. We analyzed the lattice parameters, which reveal that doping Mn into ZnO, and adsorbing NH3 and CO molecules on both ZnO and Mn-ZnO result in changes to the lattice parameters. Thus, the adsorbed molecules alter the lattice parameters, suggesting that both ZnO and Mn-ZnO have the ability to detect poisonous gases. Moreover, we also studied the band gap energy of considered materials using two functionals, PBE and PBE+U. The obtained band gap energies are closer to the experimental values when applying the PBE+U functional. Lastly, pristine ZnO, as well as CO, and NH3 adsorbed ZnO (CO-ZnO, & NH3-ZnO), are found to be non-magnetic, whereas Mn-ZnO, along with CO, and NH3 adsorbed Mn-ZnO (CO-Mn-ZnO, & NH3−Mn-ZnO) are found to be magnetic. Based on electronic and magnetic properties, considered materials are suited for sensing devices.
{"title":"First-principles study on the adsorption behavior of ZnO and Mn-doped ZnO with CO and NH3 gases","authors":"Om Shree Rijal, Hari Krishna Neupane, Pitamber Shrestha, Shriram Sharma, Leela Pradhan Joshi, Rajendra Parajuli","doi":"10.1016/j.susc.2025.122810","DOIUrl":"10.1016/j.susc.2025.122810","url":null,"abstract":"<div><div>The present work investigates the structural, electronic, and magnetic properties of a (3 × 3 × 1) supercell monolayer of Mn doped ZnO (Mn-ZnO), CO adsorbed on ZnO (CO-ZnO), NH<sub>3</sub> adsorbed on ZnO (NH<sub>3</sub>-ZnO), and CO & NH<sub>3</sub> adsorbed on Mn-ZnO (CO-Mn-ZnO, & NH<sub>3</sub>−Mn-ZnO) structures. Density functional theory (DFT) method with a projected augmented basis set has been used for this study, by employing two different exchange-correlation functionals: GGA-PBE and GGA-PBE+<em>U</em> through the Vienna-Ab-intio Simulation Package (VASP) software. We analyzed the lattice parameters, which reveal that doping Mn into ZnO, and adsorbing NH<sub>3</sub> and CO molecules on both ZnO and Mn-ZnO result in changes to the lattice parameters. Thus, the adsorbed molecules alter the lattice parameters, suggesting that both ZnO and Mn-ZnO have the ability to detect poisonous gases. Moreover, we also studied the band gap energy of considered materials using two functionals, PBE and PBE+<em>U</em>. The obtained band gap energies are closer to the experimental values when applying the PBE+<em>U</em> functional. Lastly, pristine ZnO, as well as CO, and NH<sub>3</sub> adsorbed ZnO (CO-ZnO, & NH<sub>3</sub>-ZnO), are found to be non-magnetic, whereas Mn-ZnO, along with CO, and NH<sub>3</sub> adsorbed Mn-ZnO (CO-Mn-ZnO, & NH<sub>3</sub>−Mn-ZnO) are found to be magnetic. Based on electronic and magnetic properties, considered materials are suited for sensing devices.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"761 ","pages":"Article 122810"},"PeriodicalIF":2.1,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144633585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-01DOI: 10.1016/j.susc.2025.122809
Hangqing Wu, Lu Yang, Liqun Wu, Xinning Li, Ruiyuan Li
In this study, we apply first-principle calculations to systematically investigate the synergistic regulation of physical properties of monolayer GeS materials by oxygen doping and biaxial strain. Theoretical calculations show that oxygen doping improves the charge uniformity of the system, and the strain enhancement reduces the degree of orbital hybridization and enhances the electron delocalization; doping broadens the bandgap of the material, which reaches a maximum at 2 % tensile strain, shrinks with increasing strain, and decreases monotonically under compressive strain. Differential charge density analysis shows that the tensile strain weakens the electronic reconfiguration of Ge-O bonds, reduces the bonding strength, and weakens the jump dipole moment; the compressive strain enhances the electron accumulation and orbital coupling, and improves the responsiveness of the material to low-energy light. The absorption spectra show that the biaxial strain decreases and blueshifts the absorption peaks, reflecting the broadening of the bandgap, while the compressive strain strengthens and redshifts the absorption peaks; in the reflectance spectra, the tensile strain diminishes the reflection peaks, while the compressive strain strengthens the reflection intensity. The study provides a theoretical basis for the energy band engineering of two-dimensional GeS materials as well as the application of flexible optoelectronic devices and tunable spectral sensors.
{"title":"Effect of applied biaxial strain in O-doped system on the optoelectronic properties of monolayer GeS","authors":"Hangqing Wu, Lu Yang, Liqun Wu, Xinning Li, Ruiyuan Li","doi":"10.1016/j.susc.2025.122809","DOIUrl":"10.1016/j.susc.2025.122809","url":null,"abstract":"<div><div>In this study, we apply first-principle calculations to systematically investigate the synergistic regulation of physical properties of monolayer GeS materials by oxygen doping and biaxial strain. Theoretical calculations show that oxygen doping improves the charge uniformity of the system, and the strain enhancement reduces the degree of orbital hybridization and enhances the electron delocalization; doping broadens the bandgap of the material, which reaches a maximum at 2 % tensile strain, shrinks with increasing strain, and decreases monotonically under compressive strain. Differential charge density analysis shows that the tensile strain weakens the electronic reconfiguration of Ge-O bonds, reduces the bonding strength, and weakens the jump dipole moment; the compressive strain enhances the electron accumulation and orbital coupling, and improves the responsiveness of the material to low-energy light. The absorption spectra show that the biaxial strain decreases and blueshifts the absorption peaks, reflecting the broadening of the bandgap, while the compressive strain strengthens and redshifts the absorption peaks; in the reflectance spectra, the tensile strain diminishes the reflection peaks, while the compressive strain strengthens the reflection intensity. The study provides a theoretical basis for the energy band engineering of two-dimensional GeS materials as well as the application of flexible optoelectronic devices and tunable spectral sensors.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"761 ","pages":"Article 122809"},"PeriodicalIF":2.1,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144549903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-28DOI: 10.1016/j.susc.2025.122808
T. Stach , Md Arif Uddin , Uwe Burghaus , Trung T. Pham , Robert Sporken , Abdolvahab Seif , Alberto Ambrosetti , Pier Luigi Silvestrelli
Adsorption of ethyl ether, CH3CH2–O–CH2CH3 (or C4H10O or (CH3CH2)2O), on graphene/Si(111) (hereafter Gr/Si(111)) was characterized by kinetics (multi-mass thermal desorption spectroscopy (TDS), steady-state rate measurements) and spectroscopic (Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy) techniques as well as by density functional theory calculations (DFT) as a potential metal-free catalyst. TDS results agree with the expected fragmentation pattern of molecular ethyl ether. AES and XPS spectra collected after ethyl ether adsorption are identical with data for pristine Gr/Si(111). Therefore, ethyl ether adsorbs molecularly, consistent with large activation energies for dissociation calculated by the DFT.
通过动力学（多质量热解吸光谱（TDS）、稳态速率测量）、光谱（埃格电子能谱（AES）、x射线光电子能谱（XPS）、拉曼光谱）技术以及密度泛函理论计算（DFT），表征了乙醚CH3CH2 - o - ch2ch3（或C4H10O或（CH3CH2）2O）在石墨烯/Si(111)（以下简称Gr/Si(111)）上作为潜在无金属催化剂的吸附特性。TDS结果与预期的乙醚分子断裂模式一致。乙醚吸附后收集的AES和XPS光谱与原始Gr/Si（111）的数据一致。因此，乙醚在分子上吸附，这与DFT计算的解离活化能大一致。
{"title":"Adsorption of ethyl ether on graphene/silicon – Theory and experiment","authors":"T. Stach , Md Arif Uddin , Uwe Burghaus , Trung T. Pham , Robert Sporken , Abdolvahab Seif , Alberto Ambrosetti , Pier Luigi Silvestrelli","doi":"10.1016/j.susc.2025.122808","DOIUrl":"10.1016/j.susc.2025.122808","url":null,"abstract":"<div><div>Adsorption of ethyl ether, CH<sub>3</sub>CH<sub>2</sub>–O–CH<sub>2</sub>CH<sub>3</sub> (or C<sub>4</sub>H<sub>10</sub>O or (CH<sub>3</sub>CH<sub>2</sub>)<sub>2</sub>O), on graphene/Si(111) (hereafter Gr/Si(111)) was characterized by kinetics (multi-mass thermal desorption spectroscopy (TDS), steady-state rate measurements) and spectroscopic (Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy) techniques as well as by density functional theory calculations (DFT) as a potential metal-free catalyst. TDS results agree with the expected fragmentation pattern of molecular ethyl ether. AES and XPS spectra collected after ethyl ether adsorption are identical with data for pristine Gr/Si(111). Therefore, ethyl ether adsorbs molecularly, consistent with large activation energies for dissociation calculated by the DFT.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"761 ","pages":"Article 122808"},"PeriodicalIF":2.1,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144549902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-28DOI: 10.1016/j.susc.2025.122803
Andreas Riemann, Lauren Rankin, Dylan Henry
In this study we have systematically investigated the adsorption geometries and energies of various merocyanine/spiropyran molecules on NaCl. The molecules are closed-ring spiropyran molecules with various side groups which can be transferred into open-ring merocyanine molecules. These isomers act as molecular switches which can be triggered by different external stimuli. The underlying substrate for this study is a two-layer film of the ionic insulator sodium chloride (NaCl). Adsorption of the spiropyran molecules is mostly driven by a competition between the sets of aromatic rings being able to find configurations close to the surface which leads overall to more preferable adsorption energies. On the other hand, since the merocyanine isomer as T-conformers have a generally flat geometry, they will be able to orient themselves nearly parallel to the substrate. This leads to higher binding energies for T-conformer compared to C-conformers, which due to steric effects cannot adsorb in a flat configuration. The beginning of film growth for these molecules starts with dimer formation which can be in parallel or anti-parallel geometries. In general, the anti-parallel configurations lead to higher binding energies when oppositely charged moieties of the molecules can interact through Coulomb forces. Comparing the calculated dimer configurations to experimentally observed dimers allows us to identify the particular conformers for each merocyanine molecule which might be energetically more favorable upon adsorption on the substrate. For two molecules with similar side groups, namely benzo and naphtho merocyanine, the so-called CTT and TTC conformers form dimers with highest binding energies, whereas for nitro and methoxy merocyanine, which have a common nitro side group, the dimers with highest binding energies consist of CTC and TTT conformers.
{"title":"Dimer adsorption and identification for various spiropyran-based molecular switches using Molecular Mechanics calculations","authors":"Andreas Riemann, Lauren Rankin, Dylan Henry","doi":"10.1016/j.susc.2025.122803","DOIUrl":"10.1016/j.susc.2025.122803","url":null,"abstract":"<div><div>In this study we have systematically investigated the adsorption geometries and energies of various merocyanine/spiropyran molecules on NaCl. The molecules are closed-ring spiropyran molecules with various side groups which can be transferred into open-ring merocyanine molecules. These isomers act as molecular switches which can be triggered by different external stimuli. The underlying substrate for this study is a two-layer film of the ionic insulator sodium chloride (NaCl). Adsorption of the spiropyran molecules is mostly driven by a competition between the sets of aromatic rings being able to find configurations close to the surface which leads overall to more preferable adsorption energies. On the other hand, since the merocyanine isomer as T-conformers have a generally flat geometry, they will be able to orient themselves nearly parallel to the substrate. This leads to higher binding energies for T-conformer compared to C-conformers, which due to steric effects cannot adsorb in a flat configuration. The beginning of film growth for these molecules starts with dimer formation which can be in parallel or anti-parallel geometries. In general, the anti-parallel configurations lead to higher binding energies when oppositely charged moieties of the molecules can interact through Coulomb forces. Comparing the calculated dimer configurations to experimentally observed dimers allows us to identify the particular conformers for each merocyanine molecule which might be energetically more favorable upon adsorption on the substrate. For two molecules with similar side groups, namely benzo and naphtho merocyanine, the so-called CTT and TTC conformers form dimers with highest binding energies, whereas for nitro and methoxy merocyanine, which have a common nitro side group, the dimers with highest binding energies consist of CTC and TTT conformers.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"761 ","pages":"Article 122803"},"PeriodicalIF":2.1,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144521545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-27DOI: 10.1016/j.susc.2025.122806
Zhe Xing , Dmytro Orlov , Elsebeth Schröder
Magnesium (Mg) is an abundant metal which has been used in aviation, medicine, hydrogen energy storage, etc. However, Mg can be rather reactive, and therefore an improved understanding of corrosion and oxidation mechanisms can enhance the efficiency of these processes to control and widen applications. The study presented here investigates the mechanisms of oxidation from the initial to full monolayer stages, on two low-index Mg surfaces, Mg(0001) and Mg. By analysing the valence electron changes during the oxidation process, we reveal a connection between oxidation and electron properties, suggesting that oxygen (O) atoms preferentially adsorb in the regions of charge accumulation on the surfaces. After the adsorption of a first O atom, the charge distribution on the surface changes, and following O atoms are attracted to neighbouring charge-rich regions. In addition, the oxidized Mg-O units form geometric structures initially different from the rocksalt structure commonly reported for a fully oxidized surface. In Mg(0001), the Mg-O unit structure transitions from a wurtzite type to hexagonal, while on Mg a more perfect Mg-O unit of wurtzite structure forms.
{"title":"Exploring the evolution of magnesium oxidation mechanisms by density functional theory","authors":"Zhe Xing , Dmytro Orlov , Elsebeth Schröder","doi":"10.1016/j.susc.2025.122806","DOIUrl":"10.1016/j.susc.2025.122806","url":null,"abstract":"<div><div>Magnesium (Mg) is an abundant metal which has been used in aviation, medicine, hydrogen energy storage, etc. However, Mg can be rather reactive, and therefore an improved understanding of corrosion and oxidation mechanisms can enhance the efficiency of these processes to control and widen applications. The study presented here investigates the mechanisms of oxidation from the initial to full monolayer stages, on two low-index Mg surfaces, Mg(0001) and Mg<span><math><mrow><mo>(</mo><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn><mo>)</mo></mrow></math></span>. By analysing the valence electron changes during the oxidation process, we reveal a connection between oxidation and electron properties, suggesting that oxygen (O) atoms preferentially adsorb in the regions of charge accumulation on the surfaces. After the adsorption of a first O atom, the charge distribution on the surface changes, and following O atoms are attracted to neighbouring charge-rich regions. In addition, the oxidized Mg-O units form geometric structures initially different from the rocksalt structure commonly reported for a fully oxidized surface. In Mg(0001), the Mg-O unit structure transitions from a wurtzite type to hexagonal, while on Mg<span><math><mrow><mo>(</mo><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn><mo>)</mo></mrow></math></span> a more perfect Mg-O unit of wurtzite structure forms.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"761 ","pages":"Article 122806"},"PeriodicalIF":2.1,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144556825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-24DOI: 10.1016/j.susc.2025.122805
Yu Yang , Wei Zuo , Mingzhang Lin
This study uses density functional theory (DFT) to investigate the adsorption of volatile polonium species (Po, Po2, PbPo, H2Po, and PoOH) on Pd, Pt, Au, and Cu (1 1 1) surfaces, critical for capturing radioactive polonium in lead-bismuth eutectic (LBE) nuclear coolants. Geometric optimizations and adsorption energy calculations show Pd and Pt (1 1 1) surfaces exhibit superior adsorption for most species: monatomic Po adsorbs strongest on Pd (−3.95 eV) via covalent/orbital hybridization; Po2 and PbPo form stable dissociative/cooperative bonds on Pd/Pt; H2Po shows weak physisorption on Au/Cu due to limited orbital overlap; PoOH favors Pt through hydrogen bonding and O-M interactions. Electron density changes (Δρ(r)) and partial density of states (PDOS) confirm strong chemisorption with electron accumulation and orbital hybridization, aligning with frontier orbital theory predictions. Adsorption trends follows the order of Pd/Pt > Cu > Au and the adsorption reactivity of Po species on the Pd(1 1 1) surfaces occur most spontaneously within LBE coolant operation temperature highlight Pd as promising for filter materials, providing a theoretical basis for mitigating polonium volatility in advanced nuclear systems.
{"title":"Analyzing the capture of volatile polonium-210 in lead-bismuth eutectic coolant environments on metallic Pb, Pt, Au, and Cu (1 1 1) adsorption surfaces based on density functional theory","authors":"Yu Yang , Wei Zuo , Mingzhang Lin","doi":"10.1016/j.susc.2025.122805","DOIUrl":"10.1016/j.susc.2025.122805","url":null,"abstract":"<div><div>This study uses density functional theory (DFT) to investigate the adsorption of volatile polonium species (Po, Po<sub>2</sub>, PbPo, H<sub>2</sub>Po, and PoOH) on Pd, Pt, Au, and Cu (1 1 1) surfaces, critical for capturing radioactive polonium in lead-bismuth eutectic (LBE) nuclear coolants. Geometric optimizations and adsorption energy calculations show Pd and Pt (1 1 1) surfaces exhibit superior adsorption for most species: monatomic Po adsorbs strongest on Pd (−3.95 eV) via covalent/orbital hybridization; Po<sub>2</sub> and PbPo form stable dissociative/cooperative bonds on Pd/Pt; H<sub>2</sub>Po shows weak physisorption on Au/Cu due to limited orbital overlap; PoOH favors Pt through hydrogen bonding and O-M interactions. Electron density changes (Δρ(r)) and partial density of states (PDOS) confirm strong chemisorption with electron accumulation and orbital hybridization, aligning with frontier orbital theory predictions. Adsorption trends follows the order of Pd/Pt > Cu > Au and the adsorption reactivity of Po species on the Pd(1 1 1) surfaces occur most spontaneously within LBE coolant operation temperature highlight Pd as promising for filter materials, providing a theoretical basis for mitigating polonium volatility in advanced nuclear systems.</div></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":"761 ","pages":"Article 122805"},"PeriodicalIF":2.1,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144521544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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