Lecture 17 Bohr Model of the Atom
关于原子物理认识的英语作文
关于原子物理认识的英语作文The journey of understanding the fundamental building blocks of our universe has been a captivating and ever-evolving pursuit for scientists and thinkers alike. At the heart of this exploration lies the intriguing field of atomic physics, which delves into the intricate workings of the smallest known particles that make up the matter around us. As we delve deeper into the realm of atomic structure and behavior, we uncover a world of incredible complexity and wonder, shedding light on the very essence of our physical reality.One of the most significant milestones in the understanding of atomic physics was the groundbreaking work of Ernest Rutherford, a New Zealand-born physicist who is often referred to as the father of nuclear physics. In the early 20th century, Rutherford and his colleagues conducted a series of experiments that challenged the prevailing understanding of the atom, leading to the development of the Rutherford model of the atom. This model, which depicted the atom as a dense, positively charged nucleus surrounded by orbiting electrons, was a significant departure from the earlier plum pudding model proposed by J.J. Thomson.Rutherford's experiments involved bombarding thin sheets of gold foil with alpha particles, which are positively charged helium nuclei. The vast majority of the alpha particles passed through the foil undeflected, as expected, but a small percentage were unexpectedly deflected at large angles. This observation led Rutherford to conclude that the atom was not a solid, uniform sphere, as previously believed, but rather a dense, concentrated nucleus with a significant amount of empty space surrounding it. This groundbreaking discovery paved the way for a deeper understanding of the structure and behavior of atoms.Building upon Rutherford's work, the Danish physicist Niels Bohr further refined the understanding of atomic structure by proposing a model that incorporated the concept of quantized energy levels. Bohr's model suggested that electrons within an atom could only occupy specific, discrete energy levels, and that they could only transition between these levels by emitting or absorbing a specific amount of energy in the form of a photon. This model, known as the Bohr model of the atom, provided a more accurate description of the behavior of electrons within an atom and laid the foundation for the development of quantum mechanics.The advent of quantum mechanics, pioneered by physicists such as Max Planck, Werner Heisenberg, and Erwin Schrödinger, marked apivotal shift in our understanding of atomic physics. Quantum mechanics introduced the concept of the wave-particle duality, which posits that particles, including electrons, can exhibit both particle-like and wave-like properties. This revelation challenged the classical, deterministic view of the physical world and led to the development of probabilistic interpretations of atomic and subatomic phenomena.One of the most intriguing aspects of quantum mechanics is the principle of uncertainty, as formulated by Heisenberg. This principle states that there is a fundamental limit to the precision with which certain pairs of physical properties, such as position and momentum or energy and time, can be simultaneously measured. This limitation has profound implications for our understanding of the behavior of atoms and subatomic particles, as it suggests that the act of measurement can itself influence the outcome of an experiment.Another key concept in atomic physics is the wave function, which was in troduced by Schrödinger. The wave function is a mathematical representation of the state of a particle, and its square modulus is interpreted as the probability density of finding the particle in a particular location. The wave function evolves over time according to the Schrödinger equation, which describes the dynamics of quantum systems. The wave function's ability to represent the superposition of multiple possible states, known as quantum superposition, is acornerstone of quantum mechanics and has led to the development of groundbreaking technologies, such as quantum computing.As our understanding of atomic physics has progressed, we have also gained insights into the fundamental forces that govern the interactions between particles at the atomic and subatomic scales. These forces, known as the four fundamental forces of nature, include the strong nuclear force, the weak nuclear force, the electromagnetic force, and the gravitational force. The study of these forces and their interplay has led to the development of theories such as quantum electrodynamics (QED) and quantum chromodynamics (QCD), which provide a comprehensive description of the behavior of particles and the interactions between them.One of the most significant developments in atomic physics in recent decades has been the exploration of the behavior of atoms and molecules at extremely low temperatures, known as the field of atomic, molecular, and optical (AMO) physics. In this realm, researchers have been able to observe and manipulate the behavior of individual atoms and molecules, leading to groundbreaking discoveries and the development of technologies such as atomic clocks, Bose-Einstein condensates, and quantum sensors.The ongoing exploration of atomic physics has not only deepened our understanding of the fundamental nature of matter and energybut has also paved the way for numerous technological advancements that have transformed our world. From the development of nuclear power and medical imaging techniques to the emergence of quantum computing and nanotechnology, the insights gained from the study of atomic physics have had a profound impact on our lives and continue to shape the future of scientific and technological progress.As we continue to delve into the mysteries of the atomic world, we are reminded of the enduring power of human curiosity and the relentless pursuit of knowledge. The journey of understanding atomic physics is a testament to the human spirit, as we strive to unravel the intricacies of the universe, one particle at a time. With each new discovery and every breakthrough, we inch closer to a more comprehensive understanding of the fundamental building blocks of our reality, unlocking the potential to transform our world in ways we can scarcely imagine.。
科技英语写作
科技英语写作数词分数：Eight ninths 九分之八；three fifths 五分之三；seven tenths 十分之七；one seventh 七分之一；one fourth/a quarter 四分之一；one/a half 二分之一小数: a few tenths 零点几（十分之几）；a few hundredths 零点零几（百分之几）；a few thousandths 零点零零几（千分之几）；a few millionths 百万分之几表示：分数表示法+of a/an +单位（单数形式）例：seven parts per million=seven parts in 10的6次方百万分之七Three parts per thousand=three parts in 10的3次方千分之三A third part in 10的6次方百万分之三A seventh part in 10的3次方千分之七翻译：1.这只是汽化热的千分之几译：This is only a few thousandths of the heat of vaporization.2.这药丸重零点零几克。
译：This pill weighs a few hundredths of a gram.3.要使Vbe变化零点零几伏，就可以使基极电流发生明显的变化。
译：By varying Vbe only a few hundredths of a volt,the base current can be changed significantly.4.输出是输入的100倍。
译：The output is 100 times the input.5.其速度为光速的3/10。
译：Its speed is three tenths that of light.6.施加在该物体上的力为原来的2/5。
译：The force exerted on the body is two fifths what it was.7.这只箱子比那只重5倍。
英文版原子物理课件
1.1 Introduction
The origins of atomic physics :quantum mechanics Bohr model of the H This introductory chapter surveys some of the early ideas: Spectrum of atomic H and Bohr Theory Einstein's treatment of interaction of atom with light the Zeeman effect Rutherford scattering And so on
Shanxi University Atomic Physics
1.2 Spectrum of atomic hydrogen_3
Wavenumbers may seem rather old-fashioned but they are very useful in atomic physics
the characteristic spectrum for atoms is composed of discrete lines that are the ‘fingerprint' of the element.
In 1888, the Swedish professor J. Rydberg found that the spectral lines in hydrogen obey the following mathematical formula:
Shanxi University Atomic Physics
Lyman series: n’ = 2; 3; 4; … n = 1. Balmer (n = 2), Paschen series: (n = 3), Brackett (n = 4) and Pfund (n = 5)
氢原子光谱谱线条数
氢原子光谱谱线条数The number of spectral lines in the hydrogen atom is a fascinating topic in the field of atomic physics. It has been the subject of extensive research and has played a crucial role in the development of quantum mechanics. The hydrogen atom is the simplest atomic system, consisting of a single electron orbiting a single proton in the nucleus. Despite its simplicity, the hydrogen atom exhibits a rich spectrum with a large number of spectral lines. In this essay, we will explore the reasons behind the abundance of spectral lines in hydrogen, considering various perspectives such as energy levels, electron transitions, and the mathematical framework of quantum mechanics.One of the key factors contributing to the large number of spectral lines in hydrogen is the discrete energy levels available to the electron. According to Bohr's model of the hydrogen atom, the electron can only occupy certain energy levels, which are quantized. These energy levels are determined by the principal quantum number, n, which cantake on integer values starting from 1. The energy of each level is given by the formula E = -13.6/n^2 electron volts. As the electron transitions between different energy levels, it emits or absorbs photons with specific energies corresponding to the energy difference between the initial and final levels. This leads to the appearance of distinct spectral lines in the hydrogen spectrum.Another factor that contributes to the abundance of spectral lines in hydrogen is the possibility of various electron transitions between energy levels. When anelectron undergoes a transition from a higher energy levelto a lower one, it emits a photon with a specific energy. The wavelength of the emitted photon determines the colorof the spectral line observed. The number of possible transitions increases with the number of energy levels, resulting in a larger number of spectral lines in the hydrogen spectrum. This is why hydrogen, with itsrelatively simple energy level structure, exhibits a larger number of spectral lines compared to more complex atoms.The mathematical framework of quantum mechanicsprovides a deeper understanding of the hydrogen atom's spectral lines. In quantum mechanics, the behavior of particles is described by wave functions, which are solutions to the Schrödinger equation. The wave function of the hydrogen atom can be expressed as a product of radial and angular parts, which depend on the quantum numbers associated with the energy levels and orbital angular momentum. The radial part determines the probability distribution of finding the electron at a particular distance from the nucleus, while the angular part determines the shape of the electron's orbital. The combination of different quantum numbers leads to the formation of distinct wave functions, each associated with a specific energy level and spectral line.The concept of degeneracy also plays a role in the abundance of spectral lines in hydrogen. Degeneracy refers to the phenomenon where different states have the same energy. In the case of hydrogen, energy levels with the same principal quantum number, n, but different orbital angular momentum quantum numbers, l, have the same energy. This results in multiple states with the same energy, eachcorresponding to a different orbital shape. The existence of degenerate states increases the number of possible electron transitions and, consequently, the number of spectral lines observed in the hydrogen spectrum.In conclusion, the large number of spectral lines in the hydrogen atom can be attributed to several factors. The discrete energy levels available to the electron, the possibility of various electron transitions between these levels, the mathematical framework of quantum mechanics, and the concept of degeneracy all contribute to the abundance of spectral lines. The study of hydrogen's spectral lines has not only provided valuable insights into the behavior of atoms but has also served as a foundation for the development of quantum mechanics. The richness of the hydrogen spectrum continues to inspire scientists and deepen our understanding of the fundamental nature of matter.。
Chapter 17 – Properties of Atoms and the Periodic Table17章–原子的属性与元素周期表
certain distances from the nucleus.
4. Worked in explaining the structure and behavior of simple atoms – Not complex atoms
A. Concluded that matter could not be divided into smaller and smaller pieces forever.
B. Named the smallest pieces of matter – Atom.
The atom
The Greek Model Democritus 2. Hypothesized – Atoms were infinite in number,
Atoms – Nucleus
Neutrons – Neutral charge
(2) Mass Number – The sum of the protons and neutrons found in nucleus of an atom.
(a) Determining the number of neutrons – Subtract the Atomic Number from the Mass Number (round the number)
Basic building blocks of matter
Dalton’s Model
John Dalton – English chemist
Basic Ideas of Dalton’s Atomic Theory : A. All elements are composed of atoms – Atoms
纳米科学的基本理论
宏观金属材料电子以能带的形式存在，《kBT。 服从费料在高温条件下，其能 带可以看作是连续的。
纳米颗粒电子能级是什么？
从原子分立能级到固体能带中的能级
？
从上图我们可以预测纳米材料的能级结构
1937年，Frohlich设想自由电子局域在边长为L的立 方体内。电子能级为：
• 当N(很多)个硅原子相互接近 形成固体时，随着原子间距 的减小，其最外层3P和3S能 级首先发生相互作用，导致 能级分裂，形成N个不同的能 级。这些能级汇集成带状结 构，即能带。 • 当原子间距进一步缩小时， 3S和3P能带失去其特性而合 并成一个能带（杂化）。
•当原子间距接近原子间的平衡距离时，该能带再次分裂 为两个能带。两个能带之间的没有可能的电子态的区域， 称为禁带。在禁带上方的能带叫导带，下方的能带叫价 带。
• 只要电子密度恒定，不论颗粒大小， EF不变。 • 态密度(density of state): 即单位能量的状态数 N(E), 对于能量低于E的状态数有
V 2m E N' 2 2 3
• 氢原子的能级图
电子能量
1 me En 2 2 2 n 8 0 h
半径距离 r
4
E4
E3
E2
电子势能
E1
+e 原子核
• 2 原子间的键合 • Molecular Orbital (MO) Theory. • 当原子相互靠近时，原子的电子波函数重叠形成 分子波函数，即分子轨道。 • 通常主要是指价电子云之间的重叠。 • 例如： • The H2+ ion, interactions (both attractive and repulsive) between the single electron and two nuclei.
结构化学专业英语
The Wave Behavior of Electrons 电子的波动性Bohr’s Model of The Hydrogen Atom 氢原子的波尔模型Line Spectra 线光谱quantum numbers 量子数electron spin 电子自旋atomic orbital 原子轨道s (p/d/ f) Orbital s（p/d/f）轨道single-electron atom 单电子原子many-electron atom 多电子原子energy of orbital 轨道能量the Pauli exclusion principle 泡利不相容原理electron configuration 电子组态the periodic table 周期表row 行group 族periodic properties of the elements 元素周期律radius of atoms 原子半径ionization energy 电离能electronegativity 电负性effective nuclear charge 有效核电荷electron affinities 亲电性metals 金属nonmetals 非金属covalence bond 共价键orbital overlap 轨道重叠multiple bonds 重键量子力学quantum mechanics量子化学quantum chemistry粒子particle微观粒子microscopic particle实物粒子physical particles黑体辐射black-body radiation量子化quantization光子photon电子electron光电效应photoelectric effect波粒二象性wave-particle duality不确定关系uncertainty relation/uncertainty principle波函数wave functions算符operator动量算符momentum operator本征态eigenstate能量本征态energy eigenstate本征值eigenvalue薛定谔方程schroidinger equation态叠加原理 superposition principle of state泡利原理Pauli principle正交orthogonality归一normalizing单电子原子single-electron atom简并态degenerate state变数分离法 separation of variables量子数quantum number主量子数principal quantum number角量子数angular quantum number磁量子数magnetic quantum number自旋量子数spin quantum number自旋磁量子数spin magnetic quantum number电子云electron cloud径向分布radial distribution原子轨道atomic orbital多电子原子multi-electron atom/multiple electron atom 原子轨道能atomic orbital energy电子结合能electron binding energy基态ground state激发态excited state原子光谱atomic spectrum光谱项spectral term能态 energy state化学键chemical bond共价键covalent bond极性共价键polar covalent bond非极性共价键non-polar covalent bond分子轨道理论molecular orbital theory双原子分子diatomic molecule异核双原子分子heteronuclear diatomic molecules同核双原子分子homonuclear diatomic molecules价键理论valence bond theory分子光谱molecular spectrum拉曼光谱Raman spectrum电子能谱electron spectrum光电子能谱学photoelectron spectroscopy对称性symmetry对称操作symmetry operation对称元素symmetry elements主操作（全同操作）identity operation旋转操作rotation旋转轴rotation axis/symmetry axis反演操作inversion对称中心center of symmetry反映操作reflection镜面mirror plane/symmetry plane反轴rotoinversion axis映轴rotoreflection axis非真旋转improper rotation平移对称操作translation symmetry operator群group点群point group偶极矩dipole moment极化率polarizability手性chirality旋光性optical activity矩阵matrix特征标character多原子分子polyatomic moleculechiral molecule 手性分子enantiomorph 对映体dextro- 右旋levo- 左旋stereochemistry 立体化学stereo isomer 立体异构体covalent bond 共价键conjugated diene 共轭二烯烃conjugated system 共轭体系hybridization 杂化hybrid orbital 杂化轨道Huckel rule 休克尔规则aromatic character 芳香性infrared spectrum 红外光谱allyl cation 烯丙基正离子optical activity 旋光性carbocation 碳正离子carbanion 碳负离子hybrid orbital theory 杂化轨道理论valence shell electron pair repulsion theory 价层电子对互斥理论（VSEPR）molecular geometries 分子空间构型atomic orbital 原子轨道molecular orbital 分子轨道delocalized molecular orbital 离域分子轨道Huickel molecular orbital method 休克尔分子轨道法ethylene 乙烯butadiene 丁二烯conjugated diene 共轭二烯烃conjugated system 共轭体系allyl cation 烯丙基正离子hyperconjugation effect 超共轭效应highest occupied molecular orbital 最高占据轨道（HOMO）lowest unoccupied molecular orbital 最低空轨道（LOMO）frontier orbital theory 前线轨道理论principle of the conservation of molecular orbital symmetry 分子轨道对称守恒原理Borane 硼烷bond length 键长bond order 键级bond angle 键角bond energy 键能bond polarity 键矩dipole moment 偶极矩polarity molecule 极性分子electron configurations in octahedral complexes 八面体构型配合物的电子分布general characteristics 共性s(p/d/f)-block Elements s(p/d/f)区元素alkali metals 碱金属alkaline earth metals 碱土金属radioactivity 放射性coordination compound 配位化合物complex ion 配离子center ion 中心离子ligand 配位体coordination number 配位数coordination atom 配位原子cumulative stability constant 累积/逐级稳定常数overall stability constant 总稳定常数ethylenediamine tetraacetic acid 乙二胺四乙酸（EDTA）chelate compound 螯合物lone pair electron 孤对电子bathochromic shift 红移valence bond theory 价键理论（VB）crystal field theory 晶体场理论crystal field splitting energy 晶体场分裂能（CFSE）crystal field stabilization energy 晶体场稳定化能（CFSE）electron pairing energy 电子成对能transition metal 过渡金属octahedral complex 八面体配合物tetrahedral complex 四面体配合物square-planar complex 平面四边形配合物high-spin complex 高自旋配合物low-spin complex 低自旋配合物Jahn-Teller effect 姜-泰勒效应distortion 畸变hydration energy 水化能（水合能）hydration energy of metallic ions 金属离子水化能lattice energy 点阵能（晶格能）molecular orbital theory 分子轨道理论ligand field theory 配位场理论ligand field stabilization energy 配位场稳定化能（LFSE）empirical rule 经验规则spectrochemical series 光谱化学序列enthalpy change 焓变entropy change 熵变entropy production/increase 熵增property 性质magnetism 磁性magnetic 磁的paramagnetic 顺磁的diamagnetic 反磁的ferromagnetic 铁磁的ferrimagnetic 亚铁磁的antiferromagnetic 反铁磁的magnetic moment 磁矩nuclear magnetic moment 核磁矩permanent magnetic moment 永久磁矩anomalous magnetic moment 异常磁矩magnetic susceptibility 磁化率molar susceptibility 摩尔磁化率paramagnetic susceptibility 顺磁磁化率diamagnetic susceptibility 抗磁磁化率paramagnetic resonance 顺磁共振electron paramagnetic resonance 电子顺磁共振（EPR）electron spin resonance 电子自旋共振（ESR）electronic 电子的electric 电的nuclear magnetic resonance spectra 核磁共振谱（NMR谱）chemical shift 化学位移shielding effect 屏蔽效应crystal 晶体non-crystal 非晶体crystal structure 晶体结构metallic crystals 金属晶体ionic crystals 离子晶体covalent-network crystals 原子晶体molecular crystals 分子晶体molecular forces 分子间力intermolecular forces 分子间作用力hydrogen bonding 氢键。
研究生英语课堂演讲——激光物理
感谢语
THANKS!
However, even now these celebrated inventions allow us to rummage around in the microworld in the best spirit of Alfred Nobel — for the greatest benefit to humankind.”
The Uses
• Communications: fiber-optic communication. • Medicine: laser surgery (particularly eye surgery),cosmetic skin treatments. • Industry: cut raw materials, 3D printing. • Military: damage or destroy a target in combat,radar measurement. • Entertainment: optical discs, laser lighting displays. • Optical tweezers,chirped pulse amplification.
One of the basic physical principles is that: Every system in nature "prefers" to be in the lowest energy state. This state is called the Ground state. When energy is applied to a system, the atoms(electrons) in the material are excited, and raised to a higher energy level.