The Journal of Physical Chemistry A最新文献

{"title":"Evaluating the Importance of Conformers for Understanding the Vacuum-Ultraviolet Spectra of Oxiranes: Experiment and Theory.","authors":"Ian T Beck, Erica C Mitchell, Annabelle Webb Hill, Justin M Turney, Brandon Rotavera, Henry F Schaefer","doi":"10.1021/acs.jpca.4c04391","DOIUrl":"10.1021/acs.jpca.4c04391","url":null,"abstract":"<p><p>Vacuum-ultraviolet (VUV) absorption spectroscopy enables electronic transitions that offer the unambiguous identification of molecules. As target molecules become more complex, multifunctional species present a great challenge to both experimental and computational spectroscopy. This research reports both experimental and theoretical studies of oxiranes. Computationally, the nuclear ensemble approach has been used to accurately predict experimental spectra for a variety of molecules. However, this approach incurs great computational cost, as ensembles generally consist of thousands of geometries. The present study aims to drastically reduce the ensemble by evaluating the significance of the conformers to the predicted spectra. This approach was applied to 11 substituted oxiranes using the Conformer Rotamer Ensemble Sampling Tool (CREST) of Grimme to generate an ensemble of unique conformers determined by their Boltzmann populations. Five TD-DFT functionals (BMK, CAM-B3LYP, M06-2X, MN15, ωB97X-D) and EOM-CCSD were used to simulate the spectrum of each substituted oxirane ensemble. Computed spectra were then compared to the experiment using both qualitative and quantitative metrics. Based on these metrics, it was observed that certain conformers may not be necessary to characterize this set of oxiranes despite the temperature (323 K) of the experiment. A single conformer can then be used with TD-DFT and EOM-CCSD to replicate the experimental spectra of these medium-sized combustion species.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"10906-10920"},"PeriodicalIF":2.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142783355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic and Thermodynamic Computations for Supramolecular Assemblies between a Cr(III) and Fe(III) Single-Ion Magnet and an Fe(II) Spin-Crossover Complex.","authors":"Angel Albavera-Mata, Shuanglong Liu, Hai-Ping Cheng, Richard G Hennig, S B Trickey","doi":"10.1021/acs.jpca.4c06723","DOIUrl":"10.1021/acs.jpca.4c06723","url":null,"abstract":"<p><p>Experimental results on two supramolecular complexes in which a Cr^III or Fe^III d-orbital single-ion magnet center is embedded between a pair of Fe^II spin-crossover moieties make those two complexes interesting as possible candidates for use in quantum information technologies. We report detailed computational results for their structure and electronic properties and use the resulting data to parametrize a spin Hamiltonian that facilitates comparison with experimental results and their interpretation. Consistent with experimental results on decoherence in [Fe(ox)₃]@[Fe₂L₃]⁺, we find it to be easy-plane type while the [Cr(ox)₃]@[Fe₂L₃]⁺ system is easy-axis type.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"10929-10935"},"PeriodicalIF":2.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Autobiography of Gustavo E. Scuseria.","authors":"Gustavo E Scuseria","doi":"10.1021/acs.jpca.4c07207","DOIUrl":"https://doi.org/10.1021/acs.jpca.4c07207","url":null,"abstract":"","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"128 50","pages":"10739-10745"},"PeriodicalIF":2.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142851659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the Influence of Approximations for Simulating Valence Excited X-ray Spectra.","authors":"Thomas J Penfold, Basile F E Curchod","doi":"10.1021/acs.jpca.4c06150","DOIUrl":"10.1021/acs.jpca.4c06150","url":null,"abstract":"<p><p>First-principles simulations of excited-state X-ray spectra are becoming increasingly important to interpret the wealth of electronic and geometric information contained within femtosecond X-ray absorption spectra recorded at X-ray Free Electron Lasers (X-FELs). However, because the transition dipole matrix elements must be calculated between two excited states (i.e., the valence excited state and the final core excited state arising from the initial valence excited state) of very different energies, this can be challenging and time-consuming to compute. Herein using two molecules, protonated formaldimine and cyclobutanone, we assess the ability of <i>n</i>-electron valence-state perturbation theory (NEVPT2), equation-of-motion coupled-cluster theory (EOM-CCSD), linear-response time-dependent density functional theory (LR-TDDFT) and the maximum overlap method (MOM) to describe excited state X-ray spectra. Our study focuses in particular on the behavior of these methods away from the Franck-Condon geometry and in the vicinity of important topological features of excited-state potential energy surfaces, namely, conical intersections. We demonstrate that the primary feature of excited-state X-ray spectra is associated with the core electron filling the hole created by the initial valence excitation, a process that all of the methods can capture. Higher energy states are generally weaker, but importantly much more sensitive to the nature of the reference electronic wave function. As molecular structures evolve away from the Franck-Condon geometry, changes in the spectral shape closely follow the underlying valence excitation, highlighting the importance of accurately describing the initial valence excitation to simulate the excited-state X-ray absorption spectra.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"10826-10836"},"PeriodicalIF":2.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chlorine Substitution Effect on the S₁ Relaxation Dynamics of Chlorobenzene and Chlorophenols.","authors":"Junggil Kim, Sang Kyu Kim","doi":"10.1021/acs.jpca.4c05995","DOIUrl":"10.1021/acs.jpca.4c05995","url":null,"abstract":"<p><p>The S₁ state relaxation dynamics of chlorobenzene (CB), 3-chlorophenol (3-CP), 3-CP·H₂O, and 2-chlorophenol·H₂O (2-CP·H₂O) have been investigated by means of picosecond time-resolved pump-probe spectroscopy in a state-specific manner. For CB, the S₁ state relaxes via the S₁-S₀ internal conversion in the low internal energy region (<2000 cm^-1), whereas the direct C-Cl bond dissociation channel mediated by the upper-lying repulsive πσ_CCl* state is opened to give the rather sharp increase of the S₁ relaxation rate in the high internal energy region (>2000 cm^-1). A similar dynamic feature has been observed for 3-CP in terms of the lifetime behavior with an increase in the S₁ internal energy, suggesting that the H atom tunneling dissociation reaction from OH might contribute less compared to the internal conversion, although it is not clear at the present time whether or not the sharp increase of the S₁ relaxation rate in the high internal energy region of 3-CP (>1500 cm^-1) is entirely due to that of the internal conversion. The fact that the internal conversion is facilitated by the Cl substitution implies that the energetic location of the S₁/S₀ conical intersection should have been strongly influenced by chlorine substitution on the aromatic ring. The approximate energetic location of the saddle point of the S₁(ππ*)/πσ_CCl* conical intersection along the seam coordinate for CB or 3-CP could be inferred from the energy-dependent S₁ lifetime measurements. It is discussed in comparison with the dynamic role of the S₁(ππ*)/πσ_CCl* conical intersection, which is strongly influenced by the O-H···Cl intramolecular hydrogen bond in the rather complicated yet ultrafast S₁ relaxation dynamics of the <i>cis</i>-2-CP. The S₁ lifetimes of 3-CP·H₂O and 2-CP·H₂O reveal the importance of the conformational structures, especially in terms of the intramolecular hydrogen bonding.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"10818-10825"},"PeriodicalIF":2.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Engineering of Rotational Dynamics via Polymorph Manipulation.","authors":"Alfred Błażytko, Marzena Rams-Baron, Maria Książek, Joachim Kusz, Marek Matussek, Joanna Grelska, Marian Paluch","doi":"10.1021/acs.jpca.4c04964","DOIUrl":"10.1021/acs.jpca.4c04964","url":null,"abstract":"<p><p>We used dielectric spectroscopy to uncover the rotational dynamics of the fluorophenyl rotor in different polymorphs of two amphidynamic crystals with identical sizable cores. The rotor solid-state dynamics were investigated in various crystalline environments. We did not change the chemical structure of the crystal itself, but while maintaining the same atomic composition, we changed the arrangement of atoms in space by taking advantage of crystal polymorphism, providing an alternative approach to one based on searching for new, chemically different entities with desirable functionality. We demonstrated that via polymorph variation, we can efficiently improve rotor solid-state performance and reduce the rotational barrier height by 30%. Our findings advance the understanding of polymorph engineering as a prospective trend in amphidynamic crystal technology, which uses the phenomenon of crystal polymorphism to design crystals displaying applicable internal rotational dynamics.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"10758-10765"},"PeriodicalIF":2.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142783354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Autobiography of Gustavo E. Scuseria","authors":"Gustavo E. Scuseria*,&nbsp;","doi":"10.1021/acs.jpca.4c0720710.1021/acs.jpca.4c07207","DOIUrl":"https://doi.org/10.1021/acs.jpca.4c07207https://doi.org/10.1021/acs.jpca.4c07207","url":null,"abstract":"","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"128 50","pages":"10739–10745 10739–10745"},"PeriodicalIF":2.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142850213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theoretical Insights on the Excited State Deactivation Mechanism in Protonated Adenosine.","authors":"Mohammad Salehi, Pierre Çarçabal, Reza Omidyan","doi":"10.1021/acs.jpca.4c06496","DOIUrl":"10.1021/acs.jpca.4c06496","url":null,"abstract":"<p><p>We present herein our computational exploration of the conformational landscape and photophysical properties of protonated adenosine (AdoH⁺). Several different protonated isomers and conformers have been considered and their relevant photophysical properties have been addressed. From our <i>ab initio</i> quantum computational results, an S₁/S₀ conical intersection (CI) has been located for all considered conformers, providing a significant route for the ultrafast deactivation mechanism of the S₁ excited state of AdoH⁺. Our results are also supported by nonadiabatic dynamics (NAD) simulation results indicating the S₁ excited state lifetime of 240-300 fs for the two most stable conformers of AdoH⁺ (i.e., the most stable <i>syn</i>- and <i>anti</i>-N₃ protonated tautomers), which is comparable with protonated adenine, reported in the literature. The results confirm the ultrafast deactivation mechanism as well as photostability in nucleosides in protonated form.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"10851-10860"},"PeriodicalIF":2.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142783372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Tribute to Gustavo E. Scuseria","authors":"Matthias Ernzerhof*,&nbsp;Troy Van Voorhis* and Viktor N. Staroverov*,&nbsp;","doi":"10.1021/acs.jpca.4c0720810.1021/acs.jpca.4c07208","DOIUrl":"https://doi.org/10.1021/acs.jpca.4c07208https://doi.org/10.1021/acs.jpca.4c07208","url":null,"abstract":"","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"128 50","pages":"10737–10738 10737–10738"},"PeriodicalIF":2.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142850212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Helium Nanodroplet Infrared Spectroscopic Studies of CH₄⁺ and ¹³CH₃<sup />.","authors":"Amandeep Singh, Sofia H Allison, Andrew Abhisek A Azhagesan, Andrey F Vilesov","doi":"10.1021/acs.jpca.4c06858","DOIUrl":"10.1021/acs.jpca.4c06858","url":null,"abstract":"<p><p>In this work, CH₄⁺ cations were formed in helium droplets and investigated with infrared laser spectroscopy. The observed infrared bands are assigned to the C_2v isomer of the CH₄⁺ cation. The rotational structure of the bands remains unresolved, indicating a factor of 3 or larger decrease in the rotational constants in helium nanodroplets. We also report on the observation of the spectrum of isotopically substituted ¹³CH₃⁺ cations in He droplets, which shows a well-resolved rotational structure. The rotational constant A for rotation about the C₃ axis of CH₃⁺ in helium was found to be a factor of 1.17 smaller than in the gas phase.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":" ","pages":"10861-10866"},"PeriodicalIF":2.7,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142764523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}