US4350577A
Expired / Lapsed
US
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Electronically induced multiphoton absorption
Assignee: Honeywell International Inc
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Filing: 1979-11-13
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Granted: 1982-09-21
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Expires: 1999-11-13
Abstract
Abstract Electronic excitation of polyatomic molecules followed by nonradiative decay provides states from which efficient multiphoton infrared excitation can be achieved. Initial (electronic) excitation can be molecule-specific or isotope-selective. Subsequent multiphoton excitation has a threshold which can be an order of magnitude or more lower than for multiphoton excitation from the ground state. By this method, laser-induced chemical reactions or isotope separation can be achieved with lower infrared laser fluence and/or higher concentration of polyatomic molecules than with prior art methods.
Inventors
- 👤 Donald F. Heller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:19
CPC Classifications
B; B01; B01D; B01D59/00; B01D59/34
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
105 words
A multiphoton excitation method comprising the sequential steps of: (a) exposing a material comprising polyatomic molecules to electromagnetic radiation of a predetermined wavelength in the range from visible to ultraviolet whereby the polyatomic molecules are excited to an excited electronic state having a nonradiative lifetime for decay to an excited vibrational state of a lower electronic state and (b) exposing the material to infrared laser radiation, whereby the excited molecules that have decayed to the excited vibrational state of the lower electronic state are excited by multiphoton absorption to higher vibrational states to produce a state at which the excited molecules undergo a chemical reaction.
Claim 2
Dependent Claim
105 words
A multiphoton excitation method comprising the sequential steps of: (a) exposing a material comprising polyatomic molecules to electromagnetic radiation of a predetermined wavelength in the range from visible to ultraviolet whereby the polyatomic molecules are excited to an excited electronic state having a nonradiative lifetime for decay to an excited vibrational state of a lower electronic state and (b) exposing the material to infrared laser radiation, whereby the excited molecules that have decayed to the excited vibrational state of the lower electronic state are excited by multiphoton absorption to higher vibrational states to produce a state at which the excited molecules undergo a chemical reaction.
Claim 3
Dependent Claim
25 words
The method of claim 1 wherein a time delay between exposures is equal to or longer than the nonradiative lifetime of the excited electronic state.
Claim 4
Dependent Claim
11 words
The method of claim 1 wherein the material comprises chromium oxychloride.
Claim 5
Dependent Claim
17 words
The method of claim 1 wherein the source of the visible to ultraviolet radiation is a laser.
Claim 6
Dependent Claim
16 words
The method of claim 4 wherein the laser is a frequency doubled or tripled Nd:YAG laser.
Claim 7
Dependent Claim
13 words
The method of claim 4 wherein the laser is a tunable dye laser.
Claim 8
Dependent Claim
19 words
The method of claim 1 wherein the source of the visible to ultraviolet radiation is a high intensity lamp.
Claim 9
Dependent Claim
18 words
The method of claim 1 wherein the source of the infrared laser radiation is a CO 2 laser.
Claim 10
Dependent Claim
21 words
The method of claim 1 further comprising the step of separating the resultant reaction product from the remainder of the material.
Claim 11
Dependent Claim
156 words
An isotope enrichment and separation method comprising the sequential steps of: (a) exposing a material of polyatomic molecules comprising a particular isotope of an element and at least one other isotope of the same element to electromagnetic radiation of a predetermined wavelength in the range from visible to ultraviolet to preferentially excite the polyatomic molecules containing the particular isotope of the element to an excited electronic state having a nonradiative lifetime for decay to an excited vibrational state of a lower electronic state; (b) exposing the material to infrared laser radiation, whereby the excited molecules that have decayed to the excited vibrational state of the lower electronic state and that are enriched in the particular isotope, are excited by multiphoton absorption to higher vibrational states to produce a state at which the excited molecules undergo a chemical reaction and (c) separating the resultant reaction product, enriched in the particular isotope, from the remainder of the material.
Claim 12
Dependent Claim
156 words
An isotope enrichment and separation method comprising the sequential steps of: (a) exposing a material of polyatomic molecules comprising a particular isotope of an element and at least one other isotope of the same element to electromagnetic radiation of a predetermined wavelength in the range from visible to ultraviolet to preferentially excite the polyatomic molecules containing the particular isotope of the element to an excited electronic state having a nonradiative lifetime for decay to an excited vibrational state of a lower electronic state; (b) exposing the material to infrared laser radiation, whereby the excited molecules that have decayed to the excited vibrational state of the lower electronic state and that are enriched in the particular isotope, are excited by multiphoton absorption to higher vibrational states to produce a state at which the excited molecules undergo a chemical reaction and (c) separating the resultant reaction product, enriched in the particular isotope, from the remainder of the material.
Claim 13
Dependent Claim
10 words
The method of claim 10 wherein the material comprises formaldehyde.
Claim 14
Dependent Claim
17 words
The method of claim 10 wherein the source of the visible to ultraviolet radiation is a laser.
Claim 15
Dependent Claim
16 words
The method of claim 12 wherein the laser is a frequency doubled or tripled Nd:YAG laser.
Claim 16
Dependent Claim
19 words
The method of claim 12 wherein the source of the visible to ultraviolet radiation is a tunable dye laser.
Claim 17
Dependent Claim
19 words
The method of claim 10 wherein the source of the visible to ultraviolet radiation is a high intensity lamp.
Claim 18
Dependent Claim
18 words
The method of claim 10 wherein the source of the infrared laser radiation is a CO 2 laser.
Claim 19
Dependent Claim
42 words
The method of claim 10 further comprising before step (a): exposing the material to infrared radiation of a predetermined wavelength to preferentially excite polyatomic molecules containing the particular isotope of the element to an excited vibrational state of the ground electronic state.
References Cited (Backward Citations)
US4233125A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1985-09-20 | 1986-03-22 | 1986-09-21 | $2000.00 | Window Closed / Lapsed |
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