Recent content by Mikhail_MR

  1. M

    Water vapor absorption in THz range

    Thank you for your response. Could you please explain what deconvolution you have in mind. The figure 6a is a little bit misleading. The solid line shows a signal before Gaussian window was applied. As you can see, the fluctuations become less after some time.
  2. M

    Water vapor absorption in THz range

    Hi everyone! Terahertz time-domain spectroscopy (THz-TDS) is a spectroscopic technique that is using the radiation in the THz range. https://en.wikipedia.org/wiki/Terahertz_time-domain_spectroscopy A THz-TDS setup consists of an emitter and detector. The emitter creates a short broadband...
  3. M

    Chemical potential using Boltzmann equation

    Homework Statement I must calculate chemical potential using the Boltzmann equation in relaxation time approximation $$f=f^0-\tau v_z^2 \partial f^0/\partial z,$$ where ##f^0## is given as $$f^0 = 2(\frac{m}{2\pi\hbar})^3 \frac{1}{\exp{\beta(z)(\frac{mv^2}{2}-\mu(z))}+1}$$ I have to consider...
  4. M

    Master equation -> diffusion equation

    ##d\rho/dx## would be ##\frac{\rho_n - \rho_{n-1}}{\Delta x}## at ##x_0=n-1## and ##\frac{\rho_{n+1} - \rho_{n}}{\Delta x}## at ##x_0=n##. Then: $$d(d\rho/dx)dx= [(d\rho/dx)_{x_0=n} - (d\rho/dx)_{x_0=n-1}] / \Delta x$$. Oh, now I see it. Thank you!
  5. M

    Master equation -> diffusion equation

    Homework Statement I am trying to understand the derivation of the diffusion equation from the Master equation for a 1D chain. We have an endless 1D discrete chain. State from ##n## can jump to ##n+1## and ##n-1## with equal probabilities. The distance between chain links is ##a##. Homework...
  6. M

    Internal Energy of virial expansion

    Thank you! To the second part of the task. I can define new ##C_V\left(T, V\right)##, so that if I let ##V## to be infinite (ideal gas), I will get the internal energy of the ideal gas. So it is just $$ C_V\left(V, T\right) = 3/2 N k_B - N k_B / V \frac{d}{dt}\left(T^2 \frac{d}{dt} A\right) $$...
  7. M

    Internal Energy of virial expansion

    It is strange: $$ \frac{d\left( 1/V\right)}{dV} = -1 / V^2,$$ but it is also true, that $$ \int_V^{\infty} 1 / V^2 = - \left[1 / V\right]_V^{\infty} = - 0 + 1 / V $$
  8. M

    Internal Energy of virial expansion

    Thank you, Chestermiller. Maybe you think $$ U(T,V)=C_vT +\frac{N k_b T^2}{V} \frac{d A}{dT} $$ since ## \int_V^{\infty} 1 / V^2 = - \left[1 / V\right]_V^{\infty} = - 0 + 1 / V ##
  9. M

    Internal Energy of virial expansion

    The internal energy is a total differential. In case of an ideal gas it depends only on the specific heat capacity by constant volume. In this case I calculate using the hint something like specific heat capacity by constant temperature. I mean ##c_T## in ## dU=c_V dT + c_T dV##. But I have no...
  10. M

    Internal Energy of virial expansion

    Thank you, kuruman. I should have noticed that I can't use zero as the lower limit. If I use ## V_i ## then I get $$ U = - \left[\frac{1}{V}-\frac{1}{V_i}\right] N k_B T^2 \frac{\partial A}{\partial T} > 0 $$ How do I determine now ## A ##, so that my ## c_V ## does not depend on ## V ##
  11. M

    Internal Energy of virial expansion

    Hello, I have some trouble understanding the virial expansion of the ideal gas. 1. Homework Statement I have given the state equation: $$ pV = N k_b T \left(1+\frac{A\left(T\right)}{V}\right) $$Homework Equations [/B] and a hint how to calculate the caloric equation of state $$...
  12. M

    THz radiation detection with a conductor

    Hello! Is it possible to detect THz radiation (300 GHz - 1 THz) with conductor or dipole antenna used to detect radio waves? I know that THz radiation may be detected in spectroscopic set-ups with a photoconductive antenna based on the semiconductor. In this case, the light from laser create...
  13. M

    Analyzing diffraction pattern with ImageJ

    Hey! I have a very unusual question. It is about using ImageJ to analyze diffraction patterns from TEM. 1. Homework Statement To calculate lattice parameter I need Miller Indices from planes I can recognize in the picture, wavelength of electrons and camera length. In our instructions for...
  14. M

    Maximum position expectation value for 1D harmonic oscillator

    I have to calculate the maximum of ##\langle \hat{x} \rangle## too
  15. M

    Maximum position expectation value for 1D harmonic oscillator

    Thanks for advise, blue_leaf77. I have made my calculation new. I get 4 different sets of values. ##c_{1}=c_{2} = i/\sqrt{2}## ##c_{1}=c_{2} = -i/\sqrt{2}## ##c_{1}=i/\sqrt{2}; c_{2} = -i/\sqrt{2}## ##c_{1}=-i/\sqrt{2}; c_{2} = i/\sqrt{2}## Using your advise how to examine solutions only...
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