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dmitoliundefined

Davide Mitoli

@dmitoli
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  • Raman CPHF restart
    dmitoliundefined dmitoli

    Dear dariag,

    Yes, this might be the problem, although I was able to restart a test calculation on a small system without inserting the NODIIS keyword in the fist run. May I ask you to share your input file with us?


  • Raman CPHF restart
    dmitoliundefined dmitoli

    Dear dariag,

    A static CPHF/KS calculation can be restarted from a previous run by using the RESTART keyword inside the INTCPHF block. After running some tests we have found that the RESTART option is not compatible with the use of the DIIS convergence accelerator (active by default), therefore the NODIIS keyword must be included in the input deck of the restart calculation as well, e.g.:

    INTCPHF
    RESTART
    NODIIS
    END
    

    Every CPHF/KS run writes the necessary information for a restart to file fort.31. This file must be provided as file fort.32.

    Hope this helps!


  • interpreting Raman calculation output
    dmitoliundefined dmitoli

    Dear Jonas,

    Thanks for reaching out and being one of the most active users of these early days of the forum. Your question gives us the chance to clarify some aspects of the output file that might not be obvious to non expert users. Below, I will refer to your output file.

    Harmonic Frequencies and IR intensities

    To compute harmonic frequencies and IR intensities (with the default approach of the Berry phase) the input looks like:

    FREQCALC
    INTENS
    ENDFREQ
    

    In the output file, the following table is printed:

    HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
     EIGENVALUES (EIGV) OF THE MASS WEIGHTED HESSIAN MATRIX AND HARMONIC TRANSVERSE
     OPTICAL (TO) FREQUENCIES. IRREP LABELS REFER TO SYMMETRY REPRESENTATION
     ANALYSIS; A AND I INDICATE WHETHER THE MODE IS ACTIVE OR INACTIVE,
     RESPECTIVELY, FOR IR AND RAMAN; INTEGRATED IR INTENSITIES IN BRACKETS.
    
     CONVERSION FACTORS FOR FREQUENCIES:
          1 CM**(-1) =   0.4556335E-05 HARTREE
          1 THZ      =   0.3335641E+02 CM**(-1)
    
     HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
    
        MODES         EIGV          FREQUENCIES     IRREP  IR   INTENS    RAMAN
                 (HARTREE**2)   (CM**-1)     (THZ)             (KM/MOL)
        1-   1    0.3488E-07     40.9894    1.2288  (A  )   A (     0.40)   A
        2-   2    0.6077E-07     54.1037    1.6220  (A  )   A (     0.96)   A
        3-   3    0.6801E-07     57.2344    1.7158  (A  )   A (     2.45)   A
        4-   4    0.2238E-06    103.8371    3.1130  (A  )   A (    11.47)   A
        [...]
    

    For each mode (or set of degenerate modes) its eigenvalue (in Ha\(^2\)), harmonic frequency (in cm\(^{-1}\) and THz) and irreducible representation get printed. In addition, labels specifying whether the mode is IR/Raman active are also displayed (A and I indicate whether the mode is active or inactive, respectively).

    Raman intensities

    Raman intensities can be computed via a coupled-perturbed approach by inserting the INTRAMAN keyword followed by the INTCPHF block in the input deck:

    FREQCALC
    INTRAMAN
    INTCPHF
    END
    ENDFREQ
    

    Raman intensities are computed for each independent component of the polarizability tensor (xx, xy, xz, yy, yz, zz, labeled as "Single Crystal" in the output file) and are also averaged to mimic polycrystalline powder samples (total, parallel polarisation, perpendicular polarisation averages are printed in the output).

    POLYCRYSTALLINE ISOTROPIC INTENSITIES (ARBITRARY UNITS)
    
        MODES    FREQUENCIES           I_tot     I_par    I_perp
      ----------------------------------------------------------------
        1-   1       40.9894 (A  )      0.46      0.27      0.19
        2-   2       54.1037 (A  )      7.35      4.23      3.12
        3-   3       57.2344 (A  )     12.79      8.82      3.96
        4-   4      103.8371 (A  )     13.66      7.89      5.77
    
    SINGLE CRYSTAL DIRECTIONAL INTENSITIES (ARBITRARY UNITS)
    
        MODES    FREQUENCIES          I_xx    I_xy    I_xz    I_yy    I_yz    I_zz
      ----------------------------------------------------------------------------
        1-   1       40.9894 (A  )    0.00    0.37    0.02    0.63    0.00    0.21
        2-   2       54.1037 (A  )    3.17    0.69    0.00    4.35    3.66   10.05
        3-   3       57.2344 (A  )    3.82    3.54    0.02    3.50    0.03   27.53
        4-   4      103.8371 (A  )    2.57    1.81    0.01   16.25    3.34   19.62
    

    For more details on such polycrystalline averages, please refer to sections 8.4 and 8.7 of the CRYSTAL23 manual.

    Raman spectrum

    A continuous Raman spectrum can be simulated by use of the RAMSPEC block, as in:

    FREQCALC
    INTRAMAN
    INTCPHF
    END
    RAMSPEC
    END
    ENDFREQ
    

    The simulated spectrum is printed in an external file named RAMSPEC.DAT that contains several columns: column 1 with frequencies in cm\(^{-1}\), columns 2-4 with polycrystalline intensities (total, parallel, perpendicular), columns 5-10 with single crystal intensities (xx, xy, xz, yy, yz, zz).

    Effect of Temperature and Laser wavelength

    The effect of temperature and laser wavelength on computed Raman intensities can be accounted for by use of the RAMANEXP keyword, as in:

    FREQCALC
    INTRAMAN
    INTCPHF
    END
    RAMANEXP
    298 532
    RAMSPEC
    END
    ENDFREQ
    

    Here we set 298 K for the temperature and 532 nm for the laser wavelength. This option modifies the values of all computed Raman intensities (in the output and in the RAMSPEC.DAT file accordingly).

    Please, note that other properties (harmonic frequencies and IR intensities) are not affected by this option and thus remain unchanged in the output.

    Plots

    When CRYSPLOT reads the CRYSTAL output file it only plots the total intensity of the polycrystalline powder model.

    When CRYSPLOT reads the RAMSPEC.DAT file it plots all components:

    Screenshot 2025-03-13 at 12.47.37.png

    Other plotting tools can be used to plot specific columns of the RAMSPEC.DAT file (e.g., CRYSTALClear, gnuplot).


  • Forum Rules for the CRYSTAL Software Community
    dmitoliundefined dmitoli

    Welcome to the official forum for CRYSTAL software users! This is a space to share knowledge, find support, and connect with others interested in solid-state simulations. To maintain a productive and respectful environment, we ask all members to adhere to the following rules:

    1. Be Respectful and Professional 🀝

    Treat all members with courtesy and respect. 🌟
    Avoid using offensive, discriminatory, or inflammatory language. 🚫
    Critique ideas, not people. πŸ’‘

    2. Stay On-Topic 🎯

    Ensure your posts are relevant to CRYSTAL software, solid-state simulations, or related topics.
    Avoid spamming, advertising, or self-promotion unrelated to the forum’s purpose. 🚷

    3. Use Clear and Specific Titles πŸ–‹οΈ

    Summarize your question or discussion topic in the post title.
    Avoid vague titles like "Help needed" or "Question." πŸ€”

    4. Provide Context and Details πŸ› οΈ

    When asking for support, include:
    A clear description of the issue.
    Relevant input/output files or error messages (as text or attachments, not screenshots). πŸ“„
    Your system configuration and code version (i.e., CRY23-MPP, CRY17,...).
    Avoid posting confidential or sensitive data. πŸ”’

    5. Avoid Duplicate Posts πŸ”

    Use the search function to check if your question has already been answered. πŸ€“
    If a similar thread exists, contribute to it instead of starting a new one. 🧡

    6. Follow Technical Posting Guidelines πŸ’»

    Use code blocks or formatting tools for any code and error message. πŸ“‘
    Ensure attachments are in accepted formats (.d12, .d3, .out., .outp, .dat, .png, .jpg, .txt).

    7. No Unauthorized Sharing of Software or Licenses πŸ”‘

    Do not share CRYSTAL software or any other proprietary content.
    Discussions about bypassing licensing restrictions are strictly prohibited. 🚫

    8. Moderation and Reporting πŸ›‘οΈ

    Moderators reserve the right to edit, move, or delete posts that violate these rules.
    If you see inappropriate content, report it. πŸ“’

    9. Keep the Community Inclusive 🌍

    Encourage and support new users. πŸ‘‹
    Avoid gatekeeping or discouraging questions from beginners. 🐣

    10. Follow Legal and Ethical Guidelines βš–οΈ

    Ensure your contributions comply with copyright laws and ethical standards. πŸ“œ
    Cite sources where applicable. πŸ”—

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