band spectrum

Also found in: Dictionary.

Band spectrum

A spectrum consisting of groups or bands of closely spaced lines. Band spectra are characteristic of molecular gases or chemical compounds. When the light emitted or absorbed by molecules is viewed through a spectroscope with small dispersion, the spectrum appears to consist of very wide asymmetrical lines called bands. These bands usually have a maximum intensity near one edge, called a band head, and a gradually decreasing intensity on the other side. In some band systems the intensity shading is toward shorter waves, in others toward longer waves. Each band system consists of a series of nearly equally spaced bands called progressions; corresponding bands of different progressions form groups called sequences.

When spectroscopes with adequate dispersion and resolving power are used, it is seen that most of the bands obtained from gaseous molecules actually consist of a very large number of lines whose spacing and relative intensities, if unresolved, explain the appearance of bands of continua. For the quantum-mechanical explanations of the details of band spectra See Molecular structure and spectra.

McGraw-Hill Concise Encyclopedia of Physics. © 2002 by The McGraw-Hill Companies, Inc.

band spectrum

A spectrum consisting of one or more bands of emitted or absorbed radiation. The bands consist of numbers of closely spaced lines and result from transitions between energy levels in molecules, allowing different levels of vibration or rotation.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

band spectrum

[′band ‚spek·trəm]
A spectrum consisting of groups or bands of closely spaced lines in emission or absorption, characteristic of molecular gases and chemical compounds. Also known as band.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
It retained its 900 MHz holding in Himachal Pradesh and Madhya Pradesh besides acquiring 800 MHz spectrum afresh in Assam, North-East, Odisha and West Bengal where it lost 900 MHz band spectrum holding.
The company has already acquired 1,800 MHz band spectrum in 14 circles through the 2G auction and the eight circles of Videocon would give it a nationwide reach.
India, March 15 -- In what is believed to be a serious jolt to Bharti Airtel and Vodafone, the Department of Telecom has reportedly refused to grant extension of the operators' licences along with their current 900MHz band spectrum. The telecom department stressed the licence has been de-linked from the spectrum, and that the companies will have to participate in the auction and win to regain licence
He added that the 700 band spectrum is currently being used by security services, and that the ministry is working to obtain it.
ISRO was to design, build and launch two S- band spectrum satellites for Devas to offer a range of commercial multimedia broadband services across India.
In fact, Clearwire high band spectrum is Sprint's bargaining chip in the planned merger with T-Mobile which in possession of more low-frequency spectrum.
New Delhi: India's Department of Telecom will take about 2 months to allocate 1800 Mhz band spectrum won by companies in the February auction.
Bharti Airtel and Vodafone will have to bid aggressively to retain the prime 900 MHz band spectrum in the lucrative Delhi, Mumbai and Kolkata circles as their licences expire in November and Mukesh Ambani- led Reliance Jio ( RJI) will also compete against them.
"The February 2, 2012 order will have no bearing on litigation relating to 900 MHz band," the bench said, adding that it (900 MHz band spectrum) was not the subject matter before it.
New Delhi, Jan.2 ( ANI ): The Telecom Regulatory Authority of India (TRAI) has released a consultation paper on reserve price for auction of 800 MHz Band spectrum.
The Telecom Commission, the highest decisionmaking body of DoT, last week decided to overrule Trai as it was of the view that it could earn revenue through the sale of the 800 MHz band spectrum and reduce the fiscal deficit.