What is Spectra: Definition and 283 Discussions

Bantam Spectra is the science fiction division of American publishing company Bantam Books, which is owned by Random House.
According to their website, Spectra publishes "science fiction, fantasy, horror, and speculative novels from recognizable authors". Spectra authors have collectively won 31 such awards in the fields of science fiction and fantasy, and been nominated on 132 occasions. These authors include the following:

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  1. S

    A Calculating the power spectra of scalar perturbation

    I'd like to numerically calculate the power spectra of the scalar perturbation at the Hubble crossing in warm inflation, my problem is that I don't know how to do it. As I know, the Hubble crossing happens at the onset of warm inflation where the different modes become larger than the Hubble...
  2. F

    I Laser vs photodiodes and spectra

    Hi all! I would have two questions, related to laser and photodiodes spectra. 1) We know that lasers produce a very monochromatic radiation, even if they are low to moderatly expensive. That is because the emitted frequency light is dependend on Ec - Ev = Eg which is the bandgap. So electrons...
  3. J

    I Emission spectra of different materials

    I have some more detailed questions on this further on but I found it better to start with a very basic question first: If higher temperature is correlated with shorter emitting wavelengths, how come there are incandescent light bulbs that emit yellowish light but are hotter than incandescent...
  4. Rohan Patil

    I Are continous Spectra actually discrete?

    If we assume that there is a fixed charged particle and another charged particle is spiraling down towards it, it emits electromagnetic waves as it is accelerated motion. We get a continuous spectrum. Now, if I allow the emitted photons to fall on a very photosensitive material, whose efficiency...
  5. W

    Get vibration frequency form absorption spectra line

    Homework Statement [/B] "Absorption spectra of gaeous HCl show a line at 3.5 μm which results form molecular vibration (oscillation from interatomic distance)" How do I get the frequency of vibration from this? Homework Equations ? If I knew this, then I could probably solve the problem The...
  6. F

    A Deconvolution of the optical absorption spectra

    Hi people, i am doing the deconvolution of the optical absorption spectra of some quartz samples . The optical absorption spectra were obtained following a step annealing procedure.For the deconvolution i am using the Origin 9, so my question is.. Why in some articles i find the deconvolution...
  7. Xilus

    I Equation for modeling atomic spectra of all atoms

    I've seen the equation I think is just for hydrogen. is this just for hydrogen? of course this doesn't return the atomic spectra, it returns the energy. So using E=h*v and Planck's constant. a simple factor of 1/h would return the frequency. right? Energy is directly proportional to frequency...
  8. MrRobotoToo

    I Further Evidence of a 3.5 keV line in Galactic X-Ray Spectra

    That pesky 3.5 keV line just won't go away. The authors note that it's compatible with dark matter composed of 7.02 keV sterile neutrinos. If such is the case, the Majorana mass scale of the seesaw mechanism needn't coincide with the GUT scale (if such a scale even exists).
  9. TheSodesa

    Amplitude and phase spectra from fundamental frequency?

    Homework Statement Let \begin{equation*} f(t) = 2 + \cos\left( 3t - \frac{\pi}{6} \right) + \frac{1}{4}\cos\left( \frac{1}{2}t + \frac{\pi}{3} \right) + \sin^2(t) \end{equation*} Determine the period ##T## and fundamental frequency ##\omega_0## of ##f## and draw images of its amplitude and...
  10. F

    Line Spectra correct intepretation

    Hello Forum, I understand that an electron inside an atom/molecule has many possible transitions that it can make from a higher energy state (once it is excited there) to a lower energy state (possibly the ground state but not necessarily). For example, the electron can jump directly from...
  11. H

    B Can Anti-Atoms Produce an Optical Spectrum? New Study Shows Promising Results

    thought this would be an interesting article; http://physicsworld.com/cws/article/news/2016/dec/19/antiatoms-yield-their-first-optical-spectrum
  12. ORF

    A How the emission spectra can be affected by E/M field?

    Hello A friend of mine asked me if he could improve the (amateur) characterization of minerals by studying the absorption spectra during the application of a magnetic field. I thought that maybe the electron cyclotron resonance could work, but then I noticed that very low temperatures are...
  13. Mark Harder

    Anti-hydrogen molecular spectra?

    I'm not a molecular physicist, so my speculations are bound to be somewhat naive. I'm only hoping to initiate some discussion around the subject, which I thought might be interesting to all. Now that the electronic absorption spectrum of the atomic anti-hydrogen 1s->2s electronic transition...
  14. G

    I Discrete vs Continuous Spectra in Blackbody Radiation?

    I was reading this article which talks about the theoretical model behind blackbody spectra: http://www.cv.nrao.edu/course/astr534/BlackBodyRad.html At the start, it mentions standing waves in a cavity. Standing waves in this model consist of an integer number of wavelengths. The standing waves...
  15. Domenico94

    Continuous and discrete spectra

    Is there any way to convert a continuous, aperiodic spectrum, to a discrete spectrum, in a signal? If so, would part of he energy of this signal be lost, I am this process of conversion, or would it be " distributed" amomg the various frequencies?
  16. nucleon

    Confused about magnesium's and calcium's emission spectra

    I have read that magnesium’s flame is white, and the light emitted includes all the wavelengths of visible light. Calcium, on the other hand, needs less energy to excite its valence electron, and hence, during emission, the radiation given off has a longer wavelength (red light) and its flame is...
  17. Metals

    B Photoelectric effect and atomic excitation

    A few quick questions I'd like cleared up:1) Alkali metals are said to have a really low threshold energy, enough for visible light to cause the photoelectric effect. Does this mean if I aim a flashlight (turned on) at a piece of sodium, I could ionise it? Simply flashing a light over a piece of...
  18. chobo

    I Understanding r^t & a: Seeking Clarification on Raman Spectra

    Hi all, I am studying in Raman spectra and I don't know that what's means r^t a r =1. r^t is r transpose, r^t=(x,y,z). And a is diagonalized polarizability tensor. Whats means that is equal 1? Just normailzation? Help me,and so sorry my english is too bad...
  19. N

    B Emission and Absorption Spectra

    When you heat things up, they emit specific wavelengths of light, right? Like when you heat up sodium, it emits yellow. But don't things emit shorter wavelengths of light at higher temperatures? Like how hotter stars are blue and colder stars are yellow. Since stars are mostly hydrogen...
  20. A

    I X-ray spectra- bremsstrahlung and characteristic x-rays

    Hi all, In an x-ray spectrum, the curve part represents the bremsstrahlung part, and the spikes are the characteristics x-rays. Characteristic x-rays represent a discrete energy. However, in many textbooks, I noticed that the characteristic x-rays are often represented as a peak, which implies...
  21. afcsimoes

    A Emission spectra of a hot body vs. atomic emission spectra

    Consider a piece of pure Fe hot enough to have a bright white color (about 2 000 ºC, e.g.) and the characteristic yellow narrow yellow emission of the Na atom. Does the Na yellow band will be present at the thermal spectra of the pure Fe? My guess: Yes.
  22. I

    Atomic Spectra of Hydrogen and Mercury

    Homework Statement Hi! I have a a question regarding the Atomic Spectra of Hydrogen and Mercury. My problem involves the value of m and Rydberg's constant. I used a spectrometer for this lab and calculated all the necessary angles. Homework Equations See below The Attempt at a Solution...
  23. F

    I Problem identifying two spectra

    Hi everibody. I have been tasked with finding out the spectral tipe of two stars; for that, I have processed the spectres. You can find them in the links. http://postimg.org/image/5a6w2pbf5/ http://postimg.org/image/71iehdz4h/ Now, I am a little lost, I am clueless about where to look for a...
  24. L

    A Compare absorption spectra from calculation and experiment

    hi pf nice to see you. I have a question about optical absorption spectrum of nanoscale substrates. To get an absorption spectrum of nanostrucutred material, I want to perform both fdtd calculation and optical simulation. When I do fdtd calculation, I set the incident light illuminated with...
  25. T

    I Distinguishing Blackbody and Atomic Spectra of the Sun

    Scientists have measured both the blackbody spectrum and also the atomic spectra of various elements in the Sun. How do they distinguish between the two and filter out the light from either one?
  26. super_adun

    I K-beta line for the X-ray spectra of Molybdenum with Moseley

    This should be easy but I'm totally stuck here. So I'm calculating the Kβ line (emitted energy) of Molybdenum (Mo 42). I'm using Moseley's law and am moving from the M-shell to the K-shell. Recall Moseley's law is E = 13.6 eV (Z-σ)2 *1/n2. The effective formula for the energy emitted is thus...
  27. kq6up

    I Spectra Units: cm^(-1)? | KQ6UP

    I am seeing units for atomic/molecular spectra listed as ##cm^{-1}##. Is this based on the wave number ##k## for ##\Psi=Asin(kx-\phi)##? Thanks, KQ6UP
  28. M

    Why is the baseline of my spectra raised?

    Homework Statement I took 2 spectra (measuring intensity) of a blank cuvette with a spectrometer. The first time (a) I did not put a black cloth on top of cuvette/spectrometer. The second time (b) I did put a black cloth on the system. The baseline of (b) was notably higher than the baseline of...
  29. N

    I In the absorption, and emission spectra, what happens to some

    My name is Nicholas Lee, and I am studying neuroscience, and I am trying to find a way to find better ways in neuroimaging, and microscopy to see the brain better, to find better cure for Parkinson's disease, and Alzheimer's, and epilepsy If you have a four inch cubic block of glass, and carbon...
  30. T

    Jumbled up spectra of stars/glaxies

    When you look at the emission/absorption spectrum of a single element, you can clearly see various emission/absorption lines, which are characteristic of that element. However, radiation from stars/galaxies contains spectra of many elements. How do astronomers make sense of this jumbled-up...
  31. T

    Spectroscopy and the doppler effect

    So the prof shows us how to tell if an object is red shifted, by comparing two spectra (i assume of the same object). The emission lines had similar gaps but were shifted right, therefore moving away from us. How can you obtain two different spectra of the same object if it's constantly moving...
  32. NihalRi

    Spectra of Stars: Reliable Data & Quantitative Analysis

    I'm looking for reliable data of the spectra of different stars, anyone know any good resouces? Quantitative data would be best because I want to analyze it myself (not just find out something that was already on the site). Thanks in advance :)
  33. jerromyjon

    Can temperature affect the absorption and emission ranges of atomic spectra?

    Hi, everyone! I was thinking about atomic absorption/emission of photons and how they all have specific locations in the frequency zones as "lines" of missing/peak emissions. I'm curious if there is a scientifically proven/hypothesis of how the physical oscillation of atoms in molecules due to...
  34. N

    Hydrogen, Deuterium, and Tritium Ionization Spectra

    Hello Everybody, I'm looking into spectral analysis, and I couldn't find anything online about the spectra of different isotopes in discharge tubes (i.e. neon signs and the like ). Do different hydrogen isotopes have different spectra? If so, where could I find the data on the spectra? Thanks...
  35. J

    How Do Scientists Determine the Composition of a Star's Core?

    Hi pf. As I understand we know what a star is made of by looking at the absorption spectrum from a star. Since a star is a black-body it gives out a continuous spectrum of light but as this light passes through the Sun's atmosphere, certain wavelengths are absorbed depending on what the star is...
  36. A

    Hydrogen/Helium Emission Spectra Temperature Dependence

    Hi all, Does anyone know where I can find data details of how Emission Spectra depends on temperature for the following materials: Single Hydrogen Molecular Hydrogen (H2) Helium That is, as I heat up each of the above materials by themselves, from room temperature to thousands of degrees, I'd...
  37. Vaibhav DixiT

    Rotational Spectra of Diatomic Molecules

    I was wondering how Rotational Spectra of diatomic molecule can be related to Heisenberg Uncertainty principle (Qualitatively). Being a QM model where rotational energies are quantized, there should be a qualitative reasoning on lines of the uncertainty principle, right? Anyone can direct me to...
  38. H

    Hydrogen Spectra: Absorbtion in White Light Explained

    Absorbtion spectra can be be observed by passing a WHite light ( light containing Wavelength from appx. 400nm to 700nm). Now here's My confusion! if We pass this Light from Hydrogen, It should not show dark lines in continuous band. ... (as to obsorb the Light of Visible region, It's electron...
  39. H

    Simplest lens set up to reveal optical spectra of an object

    I have done basic experiments where a laser is shot thru a grating and a lens is inserted at the diffraction pattern to put the spectra back together and form an image of the grating. apart from this being the single most mind blowing experiment ever to witness I have some questions about the...
  40. C

    What is the Purpose of Fitting Supernova Remnant Spectra?

    PF, I work as a researcher at my undergraduate institution. I have to give a presentation in a week and this question always gets me. What does learning the properties of these SNRs contribute to the overall body of knowledge? What does the scientific community gain from this knowledge...
  41. M

    CERN Alice Particle spectra behavior

    So i have a question regarding the nature of the particle spectre at alice as a function of momentum. The spectre in question can be seen here. http://cerncourier.com/cws/article/cern/48325. My question is, why is it that the particle in the low momentum range are rising and the reaching a...
  42. Q

    Proper likelihood function of the ratio of two spectra

    Hello PF'ers, I am doing an unbinned likelihood analysis where I am analyzing the ratio of two spectra: \[ \frac{S_{1}(E)}{S_{2}(E)} = F(E) \] and each spectra, \[ S_{1}, S_{2} \] has its own data set. My first idea was to take the function, \[ F(E) \] and divide by the integral of...
  43. PolywellGuy

    The Spectrum for a pure electron plasma

    Hello All, In this recent Navy publication, a team of researchers said they have discovered cusp confinement. This could be a major step towards fusion power. I am working on a write up of this publication. I am trying to understand their inferometry data. As far as I can tell, the...
  44. U

    What Transitions Create Calcium's Emission Lines at These Wavelengths?

    Homework Statement Strong emission lines from calcium were observed at ##422.7nm##, ##610.3nm##, ##612.3nm##, ##616.3nm##, ##1034.9nm##, from transitions between ##4s^2##, ##4s5s## and ##4s4p##. The transition of ##422.7nm## was also observed at absorption. The singlet-triplet splitting of...
  45. P

    Chemistry Deducing a Molecular Formula from Mass Spectra

    Homework Statement When reacted with a small quantity of water, SiCl4 produces an oxychloride X, SixClyOz. The mass spectrum of X shows peaks at mass numbers 133, 149, 247, 263 and 396. You should assume that the species responsible for all these peaks contain the 16O, 35Cl and 28Si isotopes...
  46. B

    Accurately and Quickly Interpreting NMR/IR Spectra

    In examining the IR spectrum, I noted that there were peaks for CH2-x where x is bromine, methylene (2 peaks) and a peak corresponding to a methyl group; I concluded that I've synthesized n-bromobutane. Is the method I used to interpret my spectra sound? *CDCl3 was the IR solvent In addition...
  47. E

    Optimizing Copper Absorber Depth for Beta Spectra Simulation

    Hello, I am interested in computing the optimal depth of a copper absorber for Sr-90 decay electrons. I want to find a way to simulate a beta decay spectrum in C++. Have you got any idea or possible documentation on where I could start?? Thank you!
  48. neilparker62

    State of the art on H line spectra?

    Hi Here is the number for the measured frequency for hydrogen 1s to 2s transition: 2 466 061 413 187 035 Hz By way of interest, what is our most accurate theoretical calculation of this number? I've tried the ordinary Bohr formula and it is only accurate to about 4 places. I'm also...
  49. T

    Fourier analysis and continuous spectra

    So I've been self-studying from Griffiths Intro to QM to get back in shape for graduate school this fall, and I guess I'd just like some confirmation that I'm on the right track... So while I am sure there are many other applications, the one I am dealing with is eigenfunctions of an operator...
  50. U

    Rotation Spectra - Basic transition question

    Homework Statement In rotations of diatomic molecules such as HCL, the hamiltonian is found to be: \hat H = \frac{\hat L^2}{2\mu a^2} where ##\mu## is the reduced mass, a is the separation. (a) Find the energy levels and separation. (b) Explain why rotational spectra of HCl...
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