Journal of Molecular Spectroscopy最新文献

英文中文

Revisiting the microwave spectrum and molecular structure of 1-fluoronaphthalene 回顾1-氟萘的微波光谱和分子结构

IF 1.4 4区物理与天体物理 Q4 PHYSICS, ATOMIC, MOLECULAR & CHEMICAL

Journal of Molecular Spectroscopy

Pub Date : 2025-01-01 DOI: 10.1016/j.jms.2024.111968

Surabhi Gupta , Charlotte N. Cummings , Nicholas R. Walker , Elangannan Arunan

Rotational spectra of 1-fluoronaphthalene isotopologues have been recorded using a chirped-pulse Fourier transform microwave spectrometer in the 2.0–8.0 GHz frequency range using neon as a carrier gas. Ten ¹³C isotopomers (each containing only a single ¹²C/¹³C substitution) of 1-fluoronaphthalene have been assigned in natural abundance for the first time. The rotational constants A₀, B₀, and C₀ and inertial defects are determined from experimentally measured transition frequencies. For all isotopologues, the measured values of inertial defects were observed to fall within the range from −0.142 to −0.145 u Å². The negative inertial defects are attributed to the low frequency, out-of-plane bending mode of the 1-fluoronaphthalene ring, which is evidently of similar frequency in each isotopologue. The anharmonic frequency of this mode has been calculated to be 142.8 cm⁻¹ at the B3LYP-D3/cc-pVTZ level of theory, compared to 94 cm⁻¹ predicted from the inertial defect based on an empirical relation proposed by Oka. Recent, unpublished, THz Raman spectrum reveals a peak at 75 cm⁻¹, which is closer to the empirical prediction.

利用啁啾脉冲傅立叶变换微波光谱仪，以氖为载气，在2.0 ~ 8.0 GHz频率范围内记录了1-氟萘同位素物的旋转光谱。首次以自然丰度确定了10个1-氟萘的13C同位素体（每个同位素只含有一个12C/13C取代）。旋转常数A0， B0和C0和惯性缺陷由实验测量的跃迁频率确定。对于所有同位素物，观测到惯性缺陷的测量值在- 0.142到- 0.145 u Å2之间。负惯性缺陷归因于1-氟萘环的低频、面外弯曲模式，其在各同位素岩中的频率明显相似。该模态的非谐波频率在B3LYP-D3/cc-pVTZ理论水平上计算为142.8 cm−1，而根据Oka提出的经验关系从惯性缺陷预测为94 cm−1。最近，未发表的太赫兹拉曼光谱显示在75 cm−1处有一个峰值，这更接近于经验预测。

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引用次数: 0

Three-states model for calculating the X-X rovibrational transition intensities in hydroxyl radical 计算羟基自由基中X-X旋转振动跃迁强度的三态模型

IF 1.4 4区物理与天体物理 Q4 PHYSICS, ATOMIC, MOLECULAR & CHEMICAL

Journal of Molecular Spectroscopy

Pub Date : 2025-01-01 DOI: 10.1016/j.jms.2024.111977

V.G. Ushakov , A. Yu. Ermilov , E.S. Medvedev

<div><div>The best available line list of OH [Brooke et al. JQSRT, 168 (2016) 142] contains the high-quality line frequencies, yet the line intensities need refinement because the model function used to interpolate the RKR potential and to extrapolate it into the repulsion region was not analytic [Medvedev et al. Mol. Phys. doi: 10.1080/00268976.2024.2395439], and also because the coupling between the ground <math><mrow><msup><mrow><mi>X</mi></mrow><mrow><mn>2</mn></mrow></msup><mi>Π</mi></mrow></math> and first excited <math><mrow><msup><mrow><mi>A</mi></mrow><mrow><mn>2</mn></mrow></msup><msup><mrow><mi>Σ</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow></math> electronic states was treated by the perturbation theory. In this paper, we performed ab initio calculations of all necessary molecular functions at <math><mrow><mi>r</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>4</mn></mrow></math>-8.0 bohr, and then we construct fully analytic model functions entering the Hamiltonian. The model functions were fitted to both the ab initio data and the available experimental data on the line positions and energy levels, the relative line intensities, and the transition dipole moments derived from the measured permanent dipoles. The system of three coupled Schrödinger equations for two multiplet components of the <math><mi>X</mi></math> state plus the <math><mi>A</mi></math> state was solved to calculate the energy levels and the line intensities. The new set of the Einstein A coefficients permits to decrease the scatter of the logarithmic populations of the ro-vibrational levels derived from the observed radiation fluxes [Noll et al. Atmos. Chem. Phys. 20 (2020) 5269], to achieve better agreement with the measured relative intensities, and to obtain significant differences in the intensities of the <math><mi>Λ</mi></math> doublets for large <math><mi>v</mi></math> and <math><mi>J</mi></math> as observed by Noll et al. The <math><mi>X</mi></math>-<math><mi>A</mi></math> coupling fully modifies the Q-line intensities at high <math><mi>J</mi></math> by removing the well-known <math><msup><mrow><mi>J</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></math> dependence. A new line list is constructed where the transition frequencies are from Brooke et al. and the Einstein <math><mi>A</mi></math> coefficients are from the present study. However, not all the problems with the intensities were resolved, presumably due to the neglect of the interaction with the <math><mrow><msup><mrow></mrow><mrow><mn>4</mn></mrow></msup><msup><mrow><mi>Σ</mi></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mo>,</mo></mrow><mrow><mn>2</mn></mrow></msup><msup><mrow><mi>Σ</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math> and <math><mrow><msup><mrow></mrow><mrow><mn>4</mn

OH的最佳可用线列表[Brooke等]。JQSRT, 168(2016) 142]包含高质量的线频率，但线强度需要改进，因为用于插值RKR势并将其外推到排斥区域的模型函数不是解析的[Medvedev等]。摩尔。物理。[doi: 10.1080/00268976.2024.2395439]，也因为地面X2Π和第一激发态A2Σ+电子态之间的耦合是用摄动理论处理的。本文在r=0.4-8.0玻尔条件下，从头计算了所有必需的分子函数，并构造了进入哈密顿量的全解析模型函数。将模型函数拟合到从头算数据和现有的实验数据上，拟合了线的位置和能级、相对线强度以及由测量的永久偶极子得到的跃迁偶极子矩。求解了X态和A态两个多重分量的三个耦合系统Schrödinger方程，计算了能级和线强度。新的爱因斯坦A系数集允许减少由观测到的辐射通量导出的反振动能级的对数总体的散射[Noll等人]。大气压。化学。Phys. 20(2020) 5269]，以获得与测量的相对强度更好的一致性，并获得Noll等人观察到的大v和J的Λ双重态强度的显着差异。通过消除众所周知的J−2依赖性，X-A耦合完全改变了高J处的q线强度。我们构建了一个新的谱线列表，其中的跃迁频率来自Brooke等人，爱因斯坦A系数来自本研究。然而，并不是所有的强度问题都得到了解决，可能是由于忽略了与4Σ−，2Σ−和4Π的排斥电子项的相互作用。

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引用次数: 0

Free-jet absorption millimeter-wave spectrum of 2’-aminoacetophenone 2′-氨基苯乙酮的自由射流吸收毫米波光谱

IF 1.4 4区物理与天体物理 Q4 PHYSICS, ATOMIC, MOLECULAR & CHEMICAL

Journal of Molecular Spectroscopy

Pub Date : 2025-01-01 DOI: 10.1016/j.jms.2024.111966

Salvatore Boi , Sonia Melandri , Luca Evangelisti , Assimo Maris

The rotational spectrum of 2’-aminoacetophenone has been recorded and assigned using a Stark-modulated Free-Jet Absorption Millimeter-Wave (FJ-AMMW) spectrometer in the 59.6–74.4 GHz frequency range. Some transition lines show a hyperfine structure due to the internal rotation of the methyl group. A global fitting including previous measurements performed in the microwave region allowed the determination of the

D_{J}

and

D_{K}

quartic centrifugal distortion constants and methyl internal rotation barrier

V_{3}

= 644(3) cm⁻¹ value. The A–E tunnelling splitting is estimated to be

Δ_{0}

= 23 MHz. Calculations at the MP2/aug-cc-pVTZ level underestimate the height of the

V_{3}

barrier by about 23 cm⁻¹. This difference increases to 150 cm⁻¹ with B3LYP-D3(BJ)/Def2-TZVP.

利用stark调制的自由射流吸收毫米波（FJ-AMMW）光谱仪记录了2′-氨基苯乙酮在59.6-74.4 GHz频率范围内的旋转光谱。由于甲基的内旋，一些过渡线显示出超精细结构。包括先前在微波区域进行的测量在内的全局拟合允许确定DJ和DK四次离心畸变常数和甲基内旋势垒V3 = 644(3) cm−1值。A-E隧穿劈裂估计为Δ0 = 23 MHz。在MP2/aug-cc-pVTZ水平上的计算低估了V3势垒的高度约23 cm−1。使用B3LYP-D3(BJ)/Def2-TZVP后，这种差异增加到150 cm−1。

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引用次数: 0

Study of HD17O spectrum. Theory and experiment HD17O频谱的研究。理论与实验

IF 1.4 4区物理与天体物理 Q4 PHYSICS, ATOMIC, MOLECULAR & CHEMICAL

Journal of Molecular Spectroscopy

Pub Date : 2025-01-01 DOI: 10.1016/j.jms.2024.111965

Leonid N. Sinitsa , Nikolai F. Zobov , Mikhail A. Rogov , Jonathan Tennyson , Oleg L. Polyansky

A spectrum of HD¹⁷O in the region between 5 480 and 6 400

{cm}^{- 1}

recorded in Tomsk is reported. In this region 4292 lines are observed belonging to 7 water isotopologues: 536 lines – H

_{2}^{16}

O 1019 – HD¹⁶O, 122 – D

_{2}

^{16}

O, 447 – H

_{2}^{17}

O 458 – HD¹⁷O, 151 – H

_{2}^{18}

O, 181 – HD¹⁸O. A new potential energy surface (PES) of HD¹⁶O is obtained by fitting to empirical energy levels. This PES, with a diagonal Born–Oppenheimer correction (DBOC), is used to compute the HD¹⁷O spectrum. Pseudo-experimental isotopologue-extrapolation energy levels of HD¹⁷O are constructed using the method of Polyansky et al (MNRAS 466, 1363 (2017)). Assignment of the measured spectrum is conducted: 68 % of the lines can be assigned using assignments from previously published work. The remaining lines are assigned using the pseudo-experimental energy levels procedure. We compare the calculated pseudo-experimental values of energy levels with both existing 1285 experimental levels of HD¹⁷O and the 152 newly determined in this work energy levels. The standard deviation of levels with low J (up to J=10) is about 0.007

{cm}^{- 1}

in both cases. Energy levels from both pseudo-experimental and variationally calculated are also compared with newly measured HD¹⁷O lines above 10 000

{cm}^{- 1}

报道了在托木斯克记录的5 480 ~ 6 400 cm−1区域的HD17O光谱。该地区共发现7个水同位素组，共4292条，其中H216O - 1019 - HD16O 536条，D2 - 16O 122条，H217O - 458 - HD17O 447条，H218O 151条，HD18O 181条。通过对经验能级的拟合，得到了HD16O的新势能面（PES）。该PES具有对角线Born-Oppenheimer校正（DBOC），用于计算HD17O频谱。采用Polyansky等人（MNRAS 466, 1363(2017)）的方法构建HD17O的伪实验同位素外推能级。对测量频谱进行分配：68%的谱线可以使用以前发表的工作分配。其余的线是用伪实验能级程序分配的。我们将计算的伪实验能级值与HD17O现有的1285个实验能级和新确定的152个工作能级进行了比较。在两种情况下，低J水平（J=10以下）的标准偏差约为0.007 cm−1。伪实验和变分计算的能级也比较了新测量的HD17O谱线在10000 cm−1以上的能级。

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引用次数: 0

Characterization of the pyrolysis products of 2-pyrone via matrix-isolation FTIR 2-吡咯酮热解产物的基质分离FTIR表征

IF 1.4 4区物理与天体物理 Q4 PHYSICS, ATOMIC, MOLECULAR & CHEMICAL

Journal of Molecular Spectroscopy

Pub Date : 2025-01-01 DOI: 10.1016/j.jms.2024.111981

Khaled El-Shazly, Heather R. Legg, Jayden Wilkinson, David Kapp, Laura R. McCunn

One commonly observed product of the pyrolysis of many types of biomass is the cyclic oxygenated heterocycle 2-pyrone (2H-Pyran-2-one). Applying matrix-isolation techniques, the thermal decomposition products of 2-pyrone were identified by depositing a diluted mixture of sample and argon through a heated SiC tube onto a cold CsI window, which was then characterized by FT-IR. Experimental spectra collected following pyrolysis at 1400 K indicate the formation of acetylene, vinylacetylene, propargyl, propyne, allyl, carbon dioxide, carbon monoxide, ketene, and furan. Several bands in the vicinity of the antisymmetric CCO stretch of ketene are tentatively assigned to vinylketene and formylvinylketene. Computational analysis using Gaussian 09 at the B3LYP/6-311++G (d,p) level of theory was performed to further confirm product assignments. The results of this study are consistent with published theoretical and computational studies of the pyrolysis of furfural, of which 2-pyrone is a reaction intermediate.

许多类型的生物质热解的一个常见的产物是环氧杂环2-吡咯酮（2H-Pyran-2-one）。采用基质分离技术，将稀释后的样品和氩气的混合物通过加热的SiC管沉积到冷CsI窗口上，然后用FT-IR表征2-吡咯酮的热分解产物。在1400k下热解后收集的实验光谱表明，形成了乙炔、乙烯乙炔、丙炔、丙炔、烯丙基、二氧化碳、一氧化碳、烯酮和呋喃。在乙烯烯的反对称CCO拉伸附近的几个带暂定为乙烯基乙烯烯和甲酰基乙烯基乙烯烯。采用高斯09在B3LYP/6-311++G （d,p）理论水平上进行计算分析，进一步确认产品分配。本研究的结果与已发表的关于糠醛热解的理论和计算研究一致，其中2-吡酮是反应中间体。

引用次数: 0

The rotational spectroscopy of dichloromethane (CH235Cl2) in the ground state and ν4 vibrationally excited state from 11 to 750 GHz 二氯甲烷（CH235Cl2）在11 ~ 750 GHz的基态和ν4振动激发态的旋转光谱

IF 1.4 4区物理与天体物理 Q4 PHYSICS, ATOMIC, MOLECULAR & CHEMICAL

Journal of Molecular Spectroscopy

Pub Date : 2025-01-01 DOI: 10.1016/j.jms.2024.111982

Manamu Kobayashi , Kaori Kobayashi , Brian J. Esselman , R.Claude Woods , Robert J. McMahon , Satoshi Yamamoto , Hiroyuki Ozeki

The rotational spectrum of dichloromethane (methylene chloride, CH₂Cl₂) was measured with near-continuous frequency coverage from 29 to 750 GHz with 50 kHz resolution, with additional transitions around 11 GHz with 20 kHz resolution. The rest frequencies of transitions for both the vibrational ground state and first fundamental ν₄ are observed, measured, and least-squares fit. Transitions for both of these vibrational states are modeled with partial octic, distorted rotor A- and S-reduced Hamiltonians in the I^r representation with nuclear quadrupole coupling. Computed spectroscopic constants at the B3LYP/6–311+G(2d,p) level are compared to their corresponding experimental values. The partition function of dichloromethane is updated.

二氯甲烷（二氯甲烷，CH2Cl2）的旋转光谱在29至750 GHz的近连续频率范围内以50 kHz分辨率测量，在11 GHz附近以20 kHz分辨率测量额外的跃迁。对振动基态和第一基ν4的剩余跃迁频率进行了观测、测量和最小二乘拟合。这两种振动状态的跃迁都用核四极耦合下的Ir表示中的部分octic、畸变转子A-和s -约简哈密顿量来建模。将B3LYP/ 6-311 +G（2d,p）水平的计算光谱常数与相应的实验值进行了比较。更新了二氯甲烷的配分函数。

引用次数: 0

Python control of a high-resolution near-infrared spectrometer for undergraduate use Python控制的一个高分辨率近红外光谱仪，供大学生使用

IF 1.4 4区物理与天体物理 Q4 PHYSICS, ATOMIC, MOLECULAR & CHEMICAL

Journal of Molecular Spectroscopy

Pub Date : 2025-01-01 DOI: 10.1016/j.jms.2024.111983

Joshua Heuvel-Horwitz , Eisen C. Gross , Trevor J. Sears

We describe a project designed to introduce senior undergraduate chemistry and physics majors to the use of more advanced laser spectroscopic techniques and the interpretation of spectroscopic line shapes. We present a spectrometer design comprising modular components that are controlled using a single Python program with a graphical user interface (GUI). Unlike commercial Fourier transform infrared spectrometers typically used in undergraduate laboratories, this instrument can measure much higher resolution (approximately 0.001 cm⁻¹ compared to 0.5 cm⁻¹) data, with significantly higher (10⁻⁴) fractional absorption sensitivity. The modular, open

-

table design allows for easy viewing of optical components and better understanding of the operation of the instrument. We demonstrate the functionality of the spectrometer by measuring the P(23) rotational-vibrational line of the

ν_{1} + ν_{3}

combination band of acetylene at various pressures to extract a self-pressure broadening coefficient. An undergraduate laboratory assignment could also include estimating the Boltzmann constant from data for low pressure Doppler-broadened lines. An additional Python program with a GUI was built for user friendly least squares fitting of collected data. All Python codes developed are freely available on GitLab.

我们描述了一个项目，旨在向化学和物理专业的大四本科生介绍更先进的激光光谱技术的使用和光谱线形状的解释。我们提出了一种由模块化组件组成的光谱仪设计，这些组件使用带有图形用户界面（GUI）的单个Python程序进行控制。与通常用于本科实验室的商用傅里叶变换红外光谱仪不同，该仪器可以测量更高的分辨率（大约0.001 cm−1，而不是0.5 cm−1）数据，具有显著更高的分数吸收灵敏度（10−4）。模块化，开放式设计允许方便地查看光学元件和更好地了解仪器的操作。我们通过测量不同压力下乙炔ν1+ν3组合带的P（23）旋转-振动谱线来证明光谱仪的功能，以提取自压展宽系数。本科生的实验室作业也可以包括从低压多普勒加宽线的数据估计玻尔兹曼常数。另外还构建了一个带有GUI的Python程序，用于对收集的数据进行用户友好的最小二乘拟合。所有开发的Python代码都可以在GitLab上免费获得。

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引用次数: 0

Corrigendum to “westerfit: A new program for spin–torsion–rotation spectra” [J. Mol. Spectrosc. 404 (2024) 111928] “westerfit：一个新的自旋-扭转-旋转光谱程序”的勘误表[J]。Mol. Spectrosc. 404 (2024) 111928]

IF 1.4 4区物理与天体物理 Q4 PHYSICS, ATOMIC, MOLECULAR & CHEMICAL

Journal of Molecular Spectroscopy

Pub Date : 2025-01-01 DOI: 10.1016/j.jms.2024.111980

J.H. Westerfield , S.E. Worthington-Kirsch , Kyle N. Crabtree

引用次数: 0

Spectral features for systematic aluminum replacement in N2H2 and c-N4H4 isomers N2H2 和 c-N4H4 异构体中系统性铝置换的光谱特征

IF 1.4 4区物理与天体物理 Q4 PHYSICS, ATOMIC, MOLECULAR & CHEMICAL

Journal of Molecular Spectroscopy

Pub Date : 2024-11-01 DOI: 10.1016/j.jms.2024.111956

Jonathan R. Dotson, C. Zachary Palmer, Ryan C. Fortenberry

Nitrogen’s introduction into the Earth’s atmosphere may stem from interstellar dust particles delivering some form of nitrogen species at the dawn of the planet’s formation. One contributing source of the present nitrogen may be elusive aluminum nitride molecular clusters that are believed to be included within protoplanetary carbonaceous chondritic meteors. The present work utilizes explicitly correlated coupled cluster theory within theoretical spectroscopic techniques to provide rovibrational spectral data for small, cyclic aluminum nitride cluster conformers in the hopes of aiding in searches for such elusive molecules. The most intense transitions for each cluster are the Al

-

H stretches within the 5.2

- 5.6 μ m

range with the most intense transition of 584 km mol⁻¹ exhibited by

c

-Al

_{3}

_{4}

. Many clusters investigated herein also possess large dipole moments such as 4.45 D from

c -

_{4}

_{4}

in its C

_{2 v}

conformation. The intense vibrational transitions and large dipole moments for the molecules studied in this work should be instrumental for the rotational, vibrational, or rovibrational detection of aluminum nitride clusters that may shed light on the origin of the nitrogen present within the Earth’s atmosphere and may hold keys for observing other planet-forming regions.

氮进入地球大气层可能是由于在地球形成之初星际尘埃粒子提供了某种形式的氮物种。目前氮的一个来源可能是难以捉摸的氮化铝分子簇，据信这些分子簇包含在原行星碳质软玉流星中。本研究利用理论光谱学技术中的显相关耦合团簇理论，提供了小型环状氮化铝团簇构象的振动光谱数据，希望能有助于寻找这类难以捉摸的分子。每个簇最强烈的转变是 5.2-5.6μm 范围内的 Al-H 伸展，c-Al3NH4 的最强烈转变为 584 km mol-1。本文研究的许多团簇还具有较大的偶极矩，例如 C2v 构象中的 c-N4H4 具有 4.45 D 的偶极矩。这项工作中研究的分子的强烈振动转变和大偶极矩应有助于对氮化铝团簇进行旋转、振动或滚振探测，从而揭示地球大气中氮元素的来源，并为观测其他行星形成区域提供关键信息。

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引用次数: 0

High resolution laser diode spectroscopy of the hot bands of C2HD in the first overtone region of C-H stretching 对 C2HD 在 C-H 拉伸第一泛音区的热带进行高分辨率激光二极管光谱分析

IF 1.4 4区物理与天体物理 Q4 PHYSICS, ATOMIC, MOLECULAR & CHEMICAL

Journal of Molecular Spectroscopy

Pub Date : 2024-10-16 DOI: 10.1016/j.jms.2024.111955

D.M. Plastinina , A.S. Lipskaya , E.N. Chesnokov

The frequencies of C₂HD hot bands ro-vibrational lines of the first overtone of C-H stretching were measured using tunable diode lasers. To expand the measuring range to the region of the large rotational numbers, a heated gas cell was used. Measurements were made in the range R1–R36 and P2–P14 for the transition (2,0,0,1,0) ← (0,0,0,1,0), and in the range R1–R18 for the transition (2,0,0,0,1) ← (0,0,0,0,1). The rotational parameters of the upper and lower states for the band (2,0,0,1,0) ← (0,0,0,1,0) were determined. The doublet structure of ro-vibrational lines was studied. For the transition (2,0,0,1,0) ← (0,0,0,1,0), a sharp increase in the splitting value was detected at J > 25.

使用可调谐二极管激光器测量了 C-H 伸展第一泛音的 C2HD 热带 ro 振荡线的频率。为了将测量范围扩大到大旋转数区域，使用了加热气室。在 R1-R36 和 P2-P14 范围内测量了 (2,0,0,1,0) ← (0,0,0,1,0) 的转变，在 R1-R18 范围内测量了 (2,0,0,0,1) ← (0,0,0,1) 的转变。此外，还确定了(2,0,0,1,0) ← (0,0,0,1,0)带的上下态旋转参数。研究了旋转振荡线的双重结构。对于(2,0,0,1,0) ← (0,0,0,1,0)转变，在 J > 25 时检测到分裂值急剧增加。

引用次数: 0

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