98 .AI~I~LIED SPECTROSCOPY

"Peek-a-Boo" Data Retrieval in Infrared Spectroscopy*t Naomi E. Schlichter and Ellen Wallace

Central Research Department, Experimental Station

E. I. duPont de Nemours and Company, Wilmington, Delaware

Abstract

As the number off cards in the Wyandotte-ASTM system of data retrieval increase, the time to sort for an answer increases accordingly Simpler and more rapid methods of storage and retrieval are desirable This paper describes our hm~ted, but promising, experience with an inverted "peek-a-boo" system as i t applies to the particular needs of o u r l a b o r a t o r y . In this system each card represents a characteristic, and each compound has a location m the Cartesian grid of the card Holes are drilled at the location of the compound having the charac- tertst~c described by the card. A complete deck requires 250 cards and can retain mformat~on for 10,000 compounds. Searching ~s based on optical coincidence. Advantages of the system are slmphc:ty, rapidi- ty of output, ease of adding characteristics, and relatively inexpensive equipment.

Introduction

Some years ago our file of infrared reference spectra reached a size where ~t contained more in format ion than any person could hope to remember. Mechanical retent ion of the data was necessary if we were to take ful l advantage of all the data. A t that t ime we adopted the Wyando t t e - A S T M system (1) recorded on IBM cards. U n t d recent ly this system of data retr ieval has been reasonably success- ful. However , the standard deck of cards is now about 50,000. As this number has increased, the t ime required to sort for an answer has increased accordingly.

In the W y a n d o t t e - A S T M system each compound is represented by a card and all its characteristics are punched thereon. IBM cards have a capaci ty of 960 items. W i t h this system one must use an IBM keypunch and sorter. To search for each spectral or funct ional characterxstic, the complete deck of cards must go through the sorter once. O n each successive sort the deck becomes smaller ( the cards rejected in the previous sort are removed) unt i l only the desired card or cards are left . This system can be used for posmve or negat ive sorting, z.e., one can search for characteristics that are present or absent in a compound.

The work in our laboratory is concerned pr imari ly wi th ident i fy ing the funct ional groups of new compounds. The number of times a positive identif ication of a com- pound can be made is limited. Because of the nature of the work we have used the W y a n d o t t e - A S T M system for only a small f rac t ion of our problems, and the major i ty of the sorts have yielded lit t le in format ion and have been t ime consuming. The cost and inconvenience of sort ing exceeded the usefulness of the system. This si tuation led to the decision to t ry an indexing system§ that would require less t ime for data readout and simple equipment that could be convenient ly handled in the infrared lab- oratory.

"Presented at the Eastern Analytical Symposmm, New York, No- vember 15, 1961.

~Contrlbutlon No 801

§A system s~mdar to the one described m tMs paper is now being evaluated by the Am Soc Testing Mater. Committee E-13 on Ab- sorptmn Spectroscopy.

Figure I Ahcyclic

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• 1 % 1 ° • 1 .° 1

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• .~'.: [ • °% ° • I ~ I ° I " • ; I I o I '~

. i • . I ° I °." l

• ; i " ' • : ] •I°

i ;" :i

FIG. 1. PARTIALLY PUNCHED "PEEK-A-Boo" CARD

The "Peek-a-Boo" System

In principle, the "peek-a-boo" system was known at least as far back as 1915, when it was patented as an aid in ident i fy ing birds (2) . This type of system was first popularized In searching patent files by Bat ten (5 ) , and thus, the cards came to be commonly referred to as Bat ten cards.

Figure 1 is an example of a part ial ly punched "peek-a- boo" card.~ The card (gsA "' l l I A ' ' ) wi th a 1 /16- in . diam. hole can accommodate informat ion on 10,000 compounds. Each card represents one characterist ic, and an individual compound is assigned the same hole position on every card. This is exact ly the reverse of the W y a n d o t t e - A S T M system. In order to record the data that were considered essential to our problems, 250 cards were used. Therefore , only 250 cards are necessary to retain the i n fo rma tmn for 10,000 compounds, while in the W y a n d o t t e - A S T M system on IBM cards 10,000 cards are required. For readout pur- poses the cards representing the characteristics of the un- known are taken f rom the file and placed on a l ight box. The coinciding holes (i.e., where the hgh t shines th rough) m the superimposed cards designate the compounds con- taining these characteristics. A grid is used to read the number of the punch (Figure 2) .

gJonker Business Machines, Inc, Galthersburg, Md

VOL. 17, No . 4, 1963

O0 I0 20 30 40 50 60 70 80 90

O0 I0 ~0 50 &0 50 60 ~O 80 90 aou~e.,vs,~ess~^c.,.ts,~co..o.^,to re..*r.z× svsress

FIG. 2. MASTER GRID FOR DATA READOUT

It should be emphasxzed at this point that the spec~c system described here was des:gned for pos~twe sorting only. It is not meant to imply that the principles involved in a "peek-a-boo" system could not be applied successfully to negative sorting, but only that our wavelength coding may not be discrete enough for all consideratxons. These limitauons were maposed on the system with a speofic objective in mind.

The ultimate goal in undertaking this work was to establish a fast and econom,cal system for data retrieval that would be acceptable and useful to all people con- cerned with infrared data at our location. Therefore, to define the characteristics to be included in this system, several discussxon meetings were held with other interested people who had prewous experience with the ASTM sys-

TABLE I. CLASSIFICATION OF CARDS IN THE WHITE DECK

Ho B: ...... Mo ....... ioo,Ro ....... "o Sob .tutlon : (All Rin~s)

1 O Ring (not ~31 Acyellc 46 Mono 2 N aromatic I 32 Alic~elie 47 DI ~ n o t 3 S 33 Heteroc~clle 48 Trl~ Benzene 4 F -C=C- (not 34 Aromatic 49 Tetra or More

Cl aromatic) 35 Fused Allcyellc (Benzene) 6 BP-I 2~ ;-C~C- 36 Fused Meterocyelle 50 :Ortho 7 P I 37 IFused Aromatic 51 Meta 8 B I 38 13-Membered Rin 5 52 Fara

SI I 39 14-Membered Rln~ Rln~s i0 A]-TI [ 40 [5-Membered Hin 5 II -NO- 26 10he 41 16-Membered Rin 5 12 -NS- 27 [Two 42 17 or More Membered 13 -NOS- 28 lThree or More [ Rin5 24 -OS- I [ l~ Hydrocarbon 16 Perfluoro 17 Other

~3 Miscellaneous RO IHeterocycllc No

Cls 66 l-N- 76 -CH~ :~7 Trans 67 -O- 58 Splro 68 i-S- 78 -n-C:

59 S~nrmaetrical 69 '-N-O- ,79 -iso.

60 Unsymmetrical 70 i-N-8- :80 -n-C I

6] Viclnal 71 i-O-8- 72 I-N-O-S- 73 Other

Alkyl NO Olefins

86 -CH=CH~ 77 -C~Hs 87 ~C=CH~

~ 188 >c=~

-Iso-C3M 7 i89 ~C=C~

:~B 9 19o ~CRCM~ 81 ~iso~CH~CH(CH~)~ !91 -CH~CH=CH~ 82 (sec)-OH(CHs)CHzCHs 92 -CH=CHCHs 83 (tert)--C(CHm , 93 -C(tH~)=CHm B4 n-O~Hll 9~ =C(CHs)=

85 C6H 5 (Phenyl) 95 ~C~CH

~6 -C~OCM~ 97 CH~C~CH 98 x=c=x 99 -CH=CR- iOO ~C-O~C-C~

99

tern to ascertain their problems and suggesuons of items to be incorporated into any new system.

For the functional group codes the ASTM system is used m about 80% of its original form. Some code units that have not been useful for our type of problem have been consolidated, some codes have been eliminated en- tirely, but, more particularly, several characteristxcs that are useful in our work and that are not found in the original system have been added. One of the striking ad- vantages of the "peek-a-boo" concept of data storage is that an ind,vidual laboratory can add codes for specific points of interest simply by adding cards to the file with- out invalidating the basic system as employed by others. For instance, our laboratory is concerned with fluorocar- bons. To help retrieve specific information on these com- pounds, a set of codes has been added that is quite similar to those used for alkyl and olefin groupings.

TABLE II. CLASSIFICATION OF CARDS IN RED AND GREEN

No O NO

1 -C(=O)OR 21 2 -c(=o)o- (Zster) 22 3 -c(=o)o ~ !23

(Carbo~late ton) !24 4 -CHO ! 25

)O=O 126 6 o I

_~_(Halogen) 127 28 29

"7 -OC(=O)O- 30 8 !-C(=O)OC(=O)- 31 9 c(oa), 32 i0 -C(OR)~ 33 ii ~C(OR) 2 34 12 -OH 35 :~ -o- 36 14 -00- 37 15 R~O + 16 -Os - 17 P=O 18 ,Metal ~C=O

i19 i0ther

D E C K S

RJ_.D

No S No N-___O

-NO or -ON 41 )C©S 56 -C(©O)R~ -NHg 42 -C(=S)S- ~7 )N(C=O)O- ~NH 43 -C(=S)H 58 >N(C=O)N( >~- 44 -sc(=s)s- 59 (-C(=")-O- -C=N- 45 -SH (-OC(=N)O- -C(=N)N( 46 -S- ()N(C=N)O- )NC(=N)N~ 47 -SS- 60 -NCO or -OCN =NN=~)NV( OP =NNf 48 -S-(3 or more) 61 (-NO2 -N=N- or =N~R (-ON02 -N=N-N~ 49 R3S + I I(-NNOg -N~N + 50 -SF(I to 5) 162 i (-NO R4N + , (-ONO -NH4 ~i Other (-NNO ~NCN 63 -RN(=O)- -Ms 64 (=NO- >NF or -NF~ (~NO- Other (~N=O

6~ Other

No N-S No

66 (-C(-S)N= 76 (-e(=S)N~ (>NC(=S)N~ (-SC(=S)N~ 77

57 i(-C(=N)S- iONCC=N)S- i(-SC(=N)S- 78

=68 -SON or -NOS 79 69 '()NSN~ 80

(>NS- 70 (=MS- 81

(-N=S 82 (>S=N-

71 )NNC(=S)- 83 72 Other

RED GREEN

-O-S 'N° i N-O-$ li , F ..... (-C(=S)O- 186 !-NSO )C-CF- (-OC(=S)O-:ST (;RC(=O)S- (-oc(=s)s-: j -c -o Ms- [.~ -CF=CF- ( -C(=O)S- (-C(=O) NSO2- 14 : -OF=OFf (-OC(=O)S 88 ()NC(=S)O- 5 0 ( -sc(-o)s ( -C(=S)R0- _~

- C- ~SO~ 89 ()NS(Om)N( ~S=O ( -S(=O)N: "'6 -CF, ( -s(o~)o- (>Ms(of)- 7 -C~F~ (-S(=O)O- 90 (~NS(O~)O- 8 -n-C3F 7 -oso- (;Ns(=o)o- (-OS(Oa)0- 91 Other ( -os(-o)o- Other Io _o ~ ~r

9 -ISO-C3F 7

i0 -C4F 9 or above

The "peek-a-boo" type cards are available in umts of 100 in ten assorted colors. Radex Tabs can be used on the cards to make it easy to locate specific cards for both data input and retrieval. For example (Figure 1) Radex Tab position is 32. The Radex Tab may be placed at any of 100 different positions on the top of the card, and each numbered position tan be coded to represent the character- istic of that card. With the tabs present, the cards can be filed at random. In fact, the more mixed the deck is, the easier it is to locate the desired card. The white deck (Table I) has been used to cover rather general items, such as alkyl groupings, olefin groupings, and structure classifications. The numbers shown in the table refer to the individual white card assigned to the spec,fic charac- temstic. The red deck (Table II) contains the functional group codes. Codes have been added for acid hahde c u e [no. 6], P ~ O [no. 17], metal C - ~ O [no. 18], NF [no. 36], and SF [no. 50]. This table also includes a series of codes in our green deck that is for fluorocarbons.

100

TABLE I l L CLASSIFmATION OF CARDS ~N BROWN DECK

Number of Carbons

i- 1 ii - Ii

2 - 2 12 - 12

3 - 3 13 - 13

4 - ~ 14 - 14

5 - 5 15 - 15

6 - 6 16 - 16

7 - 7 17 - 17

8 - 8 18 - 18

9 - 9 19 - 19

IO - lO 2O - 2O

: o v e r 20 - 21

Number of Nitrosens

I - 22

2 - 23

3 - 2~

- 25

5 - 26

6 - 2?

over 6 - 28

Number of - 29 Oxysens

1

2 - 30

3 - 31

4 - 32

5 - 33

6 - 34

7 - 35

8 - 36

9 - 37

io - 38

over 10 - 39

Ntmaber of Sul furs

1 - 40

2 - 41

3 - 42

4 - 43

5 - 44

6 - 45

over 6 - 46

WAVELENGTH CODES

27 -3 ~x 51

32-38~ 52

3 8 5 i~ 53

i -56,u 54

i5 6 - 6 lp 55

16 i - 6 7P 56

6 7 - 7 6~ 57

7 6 7 8~ 58

7 8 8 oja 59

8 0 8 2~ 60

8 2 - 8 4~ 61

8 4 8 6la 62

8 6 - 88Jx 63

8 8 - 9 o~a 64

9 O - 9 2~ 65

9 2 - 9 4p 66

9 4 - 9 6p 67

9 6 - 9 8~a 68

9 8 - i00u 69

i0 0 - 20 2~ 70

I0 2 - lO 4~ 71

10 14 - 10 6Ja 72

10 6 - iO 8/.x 73

I0 8 - II Ola 74

ii 0 - II 5}/ 75

ll 5 - 12 0)/ 76

12 o - 12 5)a 77

12 5 - 13 O F 78

13 0 - 13 5)X 79

13 5 - 15 O~ 80

The brown deck (Table III) contains a semi-empirical formula code as well as our modified wavelength code. This perhaps is the most novel feature of our coding system. The coding is m microns but obviously could be in reciprocal cennmeters. The wavelength coding of the ASTM system (0.1 micron intervals) was designed to separate one specific compound from all others. Since much of our work involves new research compounds, there are frequently no existing spectra for comparison. It 1s help- ful to know what types of compounds produce a specific type of spectrum. Therefore, it is desirable to search our system for five to ten similar type spectra. To do this the functional group region has been dwided into seven rather large intervals. Most of the hydrogen vibrations have been covered by codes 51 and 52, the triple bond region by 53, and the double bond region by 54, 55, and 56. The finger- print area has been divided into 0.2 micron intervals up to 11.0 microns and larger increments thereafter.

If a band is located within ± 0 . 0 2 micron of a coding unit division, the band is double coded. Thus, 1{ a band peak is at 10.39 microns, it is coded both 71 and 72. This was done to allow for any differences in calibration or mechanical play in the instruments. At first it was thought that this might introduce too much "noise" into the sys- tem, but actually it has helped to separate some very simdar type spectra. Bands are coded m the order of de- creasing strength until ten to fifteen code units have been employed-preferably twelve or thirteen. The number of code units rarely coincides with the number of bands present since two or three bands may be included in the same code umt. For compounds which have less than twelve bands, such as CC14, CS2, CO2, etc., the lower limit does not apply, but the upper limit is always ob- served. In defining the bands to be coded in this manner, it is felt that some of the ambiguity in the Wyandotte- ASTM system has been removed. Everything is on a rela- tive basis rather than an absolute basis. Thus, the indi- vidual coder does not have to decide whether relatively weak bands are strong enough that they should be coded.

A P P L I E D S P E C T R O S C O P Y

o ~z ==3

1 5 ~ 2 0 4 0 6 0 8 0 100 120 150

WAVELENGTH. MICRONS o

A ~ - - O (CH2)sCH $

"~-o (CH2)3 CH3 o

WAVELENGTH CODES A B u, REGION

52 52 3 2 - 3 8

55 55 5 6 - 6 I

- - 5 6 6 [ - 67

57 57 6 7 - 76

58 58 7 6 - 78

59 59 7 8 - 80

64 64 8 8 - 9 0

66 66 9 2 - 9 4

67 67 9 4 - 9 6

68 68 9 6 - 9 8

71 71 102 -104

72 72 104-106

73 106-108

79 79 130-135

80 80 1 3 5 - 1 5 0

2 3 4 6

15 20 40 60 80 I00 120 150

WAVELENGTH, MICRONS

0 CH. /7'~'~ II I a

B ~ ' - C - OCH 2 --CH -(CH2)~'- CH 5

" C - O - C H 2 - iCH - (CH2) 4 - e l l 3

CH 3

F I G . 3 . S P E C T R A A N D W A V E L E N G T H C O D E S O F A R O M A T I C

ESTERS

I l lustrative Examples

For purposes of illustration a few representative spec- tra will be discussed. In Figure 3 the complete wavelength coding is given for two compounds. Coding differences are easily observed, and the spectral changes they represent are shown by the arrows. Using our rule of coding, the strongest ten to fifteen code units in the spectrum, all bands with an optical density of 0.2 or greater were coded. The original purpose in designing this system is fulfilled because a sort using only the strongest seven or eight bands in a spectrum yields both of these compounds as examples of the type of structure revolved and yet, by completely coding out the spectrum, the individual com- pounds are identified.

Figure 4 is another example of very similar spectra. In compound A all bands with an absorbance of 0.4 or greater were coded, while in compound B thirteen code units were used by eliminating all bands with an absorb-

. . . . . . . , , , , , , r

= : ! f U , , , , I, , , 6 , _ 7 , 20 4 0 60 80 I00 120 150 62 62 8 4 - 8 6

WAVELENGTH , MICRONS 6 5 6 5 9 0 - 9 2

A. ~ - S I C [ 3 6 8 6 8 9 6 - 9 8

8 79 79 1 B 0 - 1 3 5 15 20 4 0 60 80 100 120 150 80 80 135-150

WAVELENGTH, MICRONS

ct

Ct

FIG. 4. S P E C T R A A N D W A V E L E N G T H C O D E S O17 C H L O R I -

N A T E D A L K Y L S I L A N E S

WAVELENGTH CODES A B p. REGION

5 2 5 2 3 2 - 3 8

61 8 2 - 8 4

6 6 9 2 - 9 4

70 70 10 0 -102

74 74 108-110

75 75 110-115

76 76 115-120

77 77 1 2 0 - 1 2 5

VoL 17, No. 4, 1963 10l

151- ,~ , , , ~ , , , , , , . ~ 2 0 4 0 6 0 8 0 I00 120 150

WAVELENGTH, MICRONS

C H 3 , C = c ~ G H 3

CH 3 " " C H 3

FIG. 5. SPECTRA AND WAVELENGTIa~ CODES OF TETRA- METHYLETHYLENE

W A V E L E N G T H CODES J

52 3E- 38/~ 57 6 7 - 7 6 ~

62 8 4 - 86/~

63 8 6 - 8 8 ~

71 102-104 F

77 120-125/~

ance of less than 0.5. Absorbance figures are given to il- lustrate that the coding of bands ~s done on a relative intensity basis, not on an absolute scale, and will vary with the number of strong bands found in the spectrum.

Some trouble should be anticipated for very sym- metrical molecules where there are less than twelve or thirteen bands to be coded. Figure 5 is an example where only six codes are used for the entire spectrum. When the appropriate wavelength cards are used for sorting, 27 possible compounds are suggested. This involves too many records to check convemently. However, ff after looking at the unknown spectrum the assumption is made that this is probably a hydrocarbon and if this card lS added to the search, only four answers are left, one of which xs obviously tetramethylethylene. If by chance a wrong as- sumption were made and no answers were obtained, this would suggest that the unknown was not a hydrocarbon or that the compound was not present in the reference deck. Other assumptions might be tested, such as the com- pound being a tertiary amine or a sulfide. By removing the hydrocarbon card and replacing ~t with the tertiary amine card three answers are obtained. There ,s one answer with the sulfide card. By simply glancing at the master list of compound numbers and structures, it is obvious that none of these is the correct answer. The structures are all too complicated to yield such a simple spectrum. All of this, of course, illustrates how easy it xs to change the type of sort when usmg this system of data retrieval.

Advantages The advantages of this type of system are: 1) Spee~--

We can identify compounds in our deck of 3000 com- pounds in an average time of two to three mm. A Type 82 sorter':": can process only 600 IBM cards per rain. The complete deck of cards must go through the sorter for the first spectral or functional characteristic. On each successive sort the deck becomes smaller, but a minimum time of five rain would be required if one unique band could be used to identify the compound. We have used an average of ten codes for complete identification. There- fore, the "peek-a-boo" system is much faster than the present Wyandotte-ASTM method. 2) S,mplwlty--For

"lnternatmnal Business Machines Corporation, 590 Madison Ave, N Y. 22, N. Y.

readout a light box with appropriate alignment gutdes and a master grid is all that is reqmred. Therefore, all searches can be made m the laboratory at a desk. 3) Flex,- bdtty--Codes can be added or disregraded at will to smt individual needs by the addition or deletion of cards. 4) Ease of modifying the sort--An example of this was given in the discussion of the spectrum of (CH:3)2CzC(CH,~)e where consideratmn was given to the possibility that the the compound was a hydrocarbon, a tertiary amine or a sulfide by simply superimposing the appropriate card on the set of cards used for the wavelength sort. 5) Stabd#y - - T h e card stock is a plastic that does not appear to be damaged in the drilling or sorting process. It has been our experience that IBM cards are easily damaged in the sorter and must be replaced frequently.

Disadvantages

The disadvantages of this type of system are: 1) High input data tzme--We have found that we need 16 man- hours to complete 50 compounds. This includes two com- plete sets of coding which are checked against each other for errors and the necessary drilling time. However, this is approximately the same amount of time it takes us to prepare our own references for the Wyandotte-ASTM sys- tem. 2) Special equapment--A good drill is required with both ordinate and abscissa verniers for precise alignment of holes. 3) Separate negative deck--The same deck can- not be used for both positive and negattve sorting as in the Wyandotte-ASTM system. 4) Correction of Data-- When mistakes are discovered in existing data, such as tmpurities or human error in punching, more than the remaking of one card is reqmred. The wrong holes have to be located and filled in with Snopaket% a whste correc- tion liquid used by typists. This is not a difficult pro- cedure, but it is time consuming if the card has a high posting density.

Acknowledgment

The authors are indebted to personnel from other Com- pany departments for suggestions and criticisms. Special thanks are extended to Freeman H. Dyke, Jr., and David Westneat, formerly of the Engineering and Plastics De- partments, respectively.

Literature Cited

(1) L. E. Kuentzel, ANAL. CHEM. 23, 1413 (1951) (2) H. Taylor, Selectme Devwe, U. S. PAT. 1, 168, 468,

December 28, 1915 (3) W. E. Batten, A Punched Card System of Indexing

to Meet Specml Reqmrements, REPT. 22ND CONF,, ASSOC. SPEC. LIBRARIES AND INFORM. BUR. ( L o N - DON) 1947

Subrnttted August 6, 1962

"~'~htho-Art Products, Inc, Chicago 13, Ill.