What is Molecular physics: Definition and 12 Discussions

Molecular physics is the study of the physical properties of molecules, the chemical bonds between atoms as well as the molecular dynamics. Its most important experimental techniques are the various types of spectroscopy; scattering is also used. The field is closely related to atomic physics and overlaps greatly with theoretical chemistry, physical chemistry and chemical physics.In addition to the electronic excitation states which are known from atoms, molecules exhibit rotational and vibrational modes whose energy levels are quantized. The smallest energy differences exist between different rotational states: pure rotational spectra are in the far infrared region (about 30 - 150 μm wavelength) of the electromagnetic spectrum. Vibrational spectra are in the near infrared (about 1 - 5 μm) and spectra resulting from electronic transitions are mostly in the visible and ultraviolet regions. From measuring rotational and vibrational spectra properties of molecules like the distance between the nuclei can be specifically calculated.
One important aspect of molecular physics is that the essential atomic orbital theory in the field of atomic physics expands to the molecular orbital theory.

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  1. G

    Molecular speed distribution - most probable speed V

    Can someone explain to me what I am doing wrong? Trying to calculate the Temperature T using this formula I am trying to find T using most probable speed of atoms formula. T = (V^2) m/( 2k) I am getting riduculous T like 20x10^27. Why? If number of atoms N= 2x10^24 how do i get mass m? each...
  2. S

    I Selection Rules for a Diatomic Molecule?

    Hello! I have a question about selection rules and electronic transitions of a diatomic molecule: I can't find a good explanation about that, and there's so much confusion about the right rules to use. I studied that on Bransden-Joachain's "Physics of atoms and molecules", but there (to whom...
  3. O

    I General solution of the hydrogen atom Schrödinger equation

    Hello everyone! I have two questions which had bothered me for quite some time. I am sorry if they are rather trivial. The first is about the general solution of the hydrogen atom schrödinger-equation: We learned in our quantum mechanics class that the general solution of every quantum system...
  4. K

    What is the thickness of the drop if its radius is r?

    1. A small drop of fat floats on the surface of a liquid whose surface tension is s. Surface fat tension at the air-fat interface is s1, at the fat-liquid interface is s2. Determine the thickness of the drop if its radius is r.2. ##F=\sigma l## ##\delta P=\sigma (\frac 1 R_1 + \frac 1...
  5. A

    Term symbol of a molecule in an excited state

    Homework Statement Considering the molecule of ##C_2^+## in an excited state with valence configuration ##2\sigma_g^2## ##2\sigma_u^2## ##1\pi_u^2## ##3\sigma_g^1##. Finding all the possible term symbol. Homework Equations Term symbol ##^{2S+1}\Lambda## ##L=0 \rightarrow \Sigma## ##L=1...
  6. A

    I Rotational Spectra: ΔJ Selection Rule & Emission Part

    The selection rule for rotational spectra ##ΔJ = ±1##. Is it always true for the emission part of rotation spectra ##ΔJ = -1## and how?
  7. Ron19932017

    I Ionic bonding from a quantum mechanics point of view

    Hi all, I have a question about the quantum nature of ionic bonds. I know some ideas about molecular bonding which can combine two ground state of H atom to get a bonding state and an anti-bonding state which in the case of H2 molecules it correspond to the covalent bonding (sharing of...
  8. J

    I Localized and delocalized states, meaning? in Organics

    Looking (if possible for some of you) a concise but non mathematical explanation of the terms localization and delocalization? This questions is related to Quantum Molecular Physics. When reading a paper of Spectroscopy and allowed transitions, I encounter the following phrase " [Intersystem...
  9. samst

    Hund's cases for diatomic molecules

    Dear All, May anyone please advise me to the following questions in case of diatomic molecules: 1. How do we choose which Hund's case ((a), (b), or (c)...) that best describes a particular diatomic molecule? 2. How can we deduce from Hund's cases molecular electronic states (2s+1)ΛΩ (e,g...
  10. M

    Solid-State and molecular physics; allowed energy states

    When two objects move under the influence of their mutual force alone, we can treat the relative motion as a one-particle system of mass μ=m1m2/(m1+m2). An object of mass m2and charge -e orbits an object of mass m1 and charge +Ze. By appropriate substitutions into formulas given in the chapter...
  11. B

    Angular dependence (atomic and molecular physics)

    Homework Statement > 'from the form of the spherical harmonic function Y00=1/(sqrt(4pi)), what > can be said about the angular probability distribution of the ground state > of the hydrogen atom?' Homework Equations The Attempt at a Solution notes and textbook don't help its...
  12. G

    Molecular physics (easy stupid questions )

    [PLAIN]http://img560.imageshack.us/img560/6712/fizika5.jpg Homework Statement The electric energy is used to heat the liquid in the metalic bowl.. 1.Why is the liquid warmer at the top of the bowl than the bottom? 2. Why does the liquid's temperature raise faster if the metalic bowl has...